35 results on '"Isao Katsura"'
Search Results
2. 総合大学院大学学生セミナー -歴史と現在
- Author
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Isao, KATSURA and Mineyo, IWASE
- Abstract
新しい学術研究分野を開拓する創造性豊かで、視野の広い研究者育成が総合研究大学院大学の理念である。この実現に向けて、基盤機関の研究資源を活用した専門的な大学院教育を行いつつ、基盤機関との連携による「研究者育成のための総合教育」を進めてきている。その中でも、学生セミナーおよび学生セミナー実行委員活動は学際性および人間の総合性への志向を高めることを目的に行われている。桂 勲[学融合推進センター]岩瀬 峰代[学融合推進センター]CPIS Report -2013/02/001(Review)
- Published
- 2013
3. Ultradian rhythm in the intestine of Caenorhabditis elegans is controlled by the C-terminal region of the FLR-1 ion channel and the hydrophobic domain of the FLR-4 protein kinase
- Author
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Isao Katsura, Koutarou D. Kimura, and Yuri Kobayashi
- Subjects
Epithelial sodium channel ,biology ,Cell Biology ,biology.organism_classification ,Cell biology ,Biochemistry ,Protein kinase domain ,Genetics ,Phosphorylation ,Protein kinase A ,Caenorhabditis elegans ,Ion channel ,Intracellular ,Ultradian rhythm - Abstract
Defecation behavior in Caenorhabditis elegans is driven by an endogenous ultradian clock in the intestine. Its periods are positively regulated by FLR-1, an ion channel of the epithelial sodium channel/degenerin superfamily, and FLR-4, a protein kinase with a hydrophobic domain at the carboxyl terminus. FLR-1 has many putative phosphorylation sites in the C-terminal intracellular region. This structure implies that the periods may be regulated by the phosphorylation of FLR-1 by FLR-4, but it remains to be clarified. Here, we show that a truncated FLR-1 lacking the C-terminal intracellular region resulted in longer periods, suggesting that this region is involved in the negative regulation of defecation cycle periods. Contrary to our expectation, FLR-4 was still necessary for the function of the truncated FLR-1. Furthermore, FLR-4 containing a kinase-dead mutation or lacking the whole kinase domain was sufficient for normal defecation cycle periods. FLR-4 was necessary for the stable expression of FLR-1::GFP, and its hydrophobic domain was sufficient also for this function. FLR-1 and FLR-4 are often colocalized in the plasma membrane. These data showed an unexpected role of FLR-4: its hydrophobic domain stabilizes the FLR-1 ion channel, a key regulator of defecation cycle periods in the intestine.
- Published
- 2011
4. IFT-81 and IFT-74 are required for intraflagellar transport inC. elegans
- Author
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Keiko Gengyo-Ando, Tetsuo Kobayashi, Shohei Mitani, Takeshi Ishihara, and Isao Katsura
- Subjects
Phenocopy ,Genetics ,Cilium ,Mutant ,Chlamydomonas reinhardtii ,Cell Biology ,Biology ,biology.organism_classification ,Phenotype ,Cell biology ,Intraflagellar transport ,sense organs ,Prokaryotic cells ,Biogenesis - Abstract
Intraflagellar transport (IFT) is essential machinery for biogenesis and maintenance of cilia in many eukaryotic and prokaryotic cells. A large number of polypeptides are known to be involved in IFT, but the physiological role of each component is not fully elucidated. Here, we identified a C. elegans orthologue of a Chlamydomonas reinhardtii IFT component, IFT-81, and found that its loss-of-function mutants show an unusual behavioral property and small body size. IFT-81 is expressed in sensory neurons, and localized at the base of cilia. The similar phenotypes with ift-81 mutants were also observed in several IFT mutants, suggesting these defects are caused by inability of IFT. We also demonstrated that IFT-81 interacts and co-localizes with IFT-74, which is another putative component of IFT. The ift-74 loss-of-function mutants showed phenocopies with ift-81 mutants, suggesting IFT-81 and IFT-74 play comparable functions. Moreover, ift-81 and ift-74 mutants similarly exhibited weak anomalies in cilia formation and obvious disruptions of transport in mature cilia. Thus, we conclude that IFT-81 and IFT-74 coordinately act in IFT in C. elegans sensory cilia.
- Published
- 2007
5. Caenorhabditis elegansIntegrates the Signals of Butanone and Food to Enhance Chemotaxis to Butanone
- Author
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Isao Katsura, Takeshi Ishihara, and Ichiro Torayama
- Subjects
Journal Club ,Molecular Sequence Data ,Sensory system ,Olfactory Receptor Neurons ,Pheromones ,Memory ,medicine ,Animals ,Humans ,ASK1 ,Amino Acid Sequence ,Caenorhabditis elegans ,Protein kinase A ,Behavior, Animal ,biology ,MAP kinase kinase kinase ,Chemotaxis ,General Neuroscience ,Articles ,biology.organism_classification ,Butanones ,Associative learning ,Smell ,medicine.anatomical_structure ,Biochemistry ,Food ,Odorants ,Mutation ,Neuron ,Neuroscience ,Signal Transduction - Abstract
Behavioral plasticity induced by the integration of two sensory signals, such as associative learning, is an important issue in neuroscience, but its evolutionary origin and diversity have not been explored sufficiently. We report here a new type of such behavioral plasticity, which we call butanone enhancement, inCaenorhabditis elegansadult hermaphrodites:C. elegansspecifically enhances chemotaxis to butanone by preexposure to butanone and food. Mutant analysis revealed that this plasticity requires the AWCONolfactory neuron, whose fate is known to be determined by the NSY-1/ASK1 MAPKKK (mitogen-activated protein kinase kinase kinase) cascade as well as the DAF-11 and ODR-1 guanylyl cyclases. These proteins also control many aspects of olfactory sensation/plasticity in AWC neurons and seem to provide appropriate cellular conditions for butanone enhancement in the AWCONneuron. Butanone enhancement also required the functions of Bardet-Biedl syndrome genes in the AWCONneuron but not other genes that control ciliary transport. Furthermore, preexposure to butanone and the odor of food was enough for the enhancement of butanone chemotaxis. These results suggest that the AWCONolfactory neuron may conduct a behavioral plasticity resembling associative learning and that the functions of Bardet-Biedl syndrome genes in sensory cilia may play an important role in this plasticity.
- Published
- 2007
6. A Genome-wide Survey and Systematic RNAi-based Characterization of Helicase-like Genes in Caenorhabditis elegans
- Author
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Fumio Hanaoka, Takeshi Ishihara, Toshihiko Eki, and Isao Katsura
- Subjects
TBX1 ,helicase family ,comparative genomics ,Radiation Tolerance ,Genome ,RNA interference ,Genetics ,Animals ,Caenorhabditis elegans ,Molecular Biology ,Gene ,Genes, Helminth ,Comparative genomics ,biology ,X-Rays ,DNA Helicases ,Genomics ,General Medicine ,Full Papers ,Orphan gene ,biology.organism_classification ,Phenotype ,RNAi-based screen ,drh-3 ,Larva ,C. elegans ,RNA Interference - Abstract
Helicase-like proteins play a crucial role in nucleic acid- and chromatin-mediated reactions. In this study, we identified 134 helicase-like proteins in the nematode Caenorhabditis elegans and classified the proteins into 10 known subfamilies and a group of orphan genes on the basis of sequence similarity. We characterized loss-of-function phenotypes in RNA interference (RNAi)-treated animals for helicase family members, using the RNAi feeding method, and found several previously unreported phenotypes. Fifty-one (39.5%) of 129 genes tested showed development- or growth-defect phenotypes, and many of these genes were putative nematode homologs of essential genes in a unicellular eukaryote, budding yeast, suggesting conservation of these essential proteins in both species. Comparative analyses between these species identified evolutionarily diverged nematode proteins as well as conserved family members. Chromosome mapping of the nematode genes revealed 10 pairs of putative duplicated genes and clusters of C. elegans-specific SNF2-like genes and Helitrons. Analyses of transcriptional profile data revealed a predominantly oogenesis- and germline-enriched expression of many helicase-like genes. Finally, we identified the D2005.5(drh-3) gene in an RNAi-based screen for genes involved in resistance to X-ray irradiation. Analysis of DRH-3 will clarify the potentially novel mechanism by which it protects against X-ray-induced damage in C. elegans.
- Published
- 2007
7. 線虫で探る遺伝子と行動 (特集:総研大の脳科学 / Part 2 脳科学の最前線)
- Author
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Isao, KATSURA
- Published
- 2003
8. SDF-9, a protein tyrosine phosphatase-like molecule, regulates the L3/dauer developmental decision through hormonal signaling inC. elegans
- Author
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Kiyotaka Ohkura, Norio Suzuki, Takeshi Ishihara, and Isao Katsura
- Subjects
DNA, Complementary ,Time Factors ,Recombinant Fusion Proteins ,Green Fluorescent Proteins ,Molecular Sequence Data ,Mutant ,Protein tyrosine phosphatase ,Biology ,Dauer larva ,Models, Biological ,Alae ,Genes, Reporter ,Animals ,Tissue Distribution ,Amino Acid Sequence ,Transgenes ,Cloning, Molecular ,Tyrosine ,Caenorhabditis elegans ,Caenorhabditis elegans Proteins ,Promoter Regions, Genetic ,Molecular Biology ,Alleles ,Phylogeny ,Larva ,Base Sequence ,Models, Genetic ,Sequence Homology, Amino Acid ,fungi ,Temperature ,Embryonic stem cell ,Phenotype ,Hormones ,Cell biology ,Luminescent Proteins ,Cholesterol ,Microscopy, Fluorescence ,Mutation ,Steroids ,Protein Tyrosine Phosphatases ,Signal Transduction ,Developmental Biology - Abstract
The dauer larva of the nematode Caenorhabditis elegans is a good model system for investigating the regulation of developmental fates by environmental cues. Here we show that SDF-9, a protein tyrosine phosphatase-like molecule, is involved in the regulation of dauer larva formation. The dauer larva of sdf-9 mutants is different from a normal dauer larva but resembles the dauer-like larva of daf-9 and daf-12 dauer-constitutive mutants. Like these mutants, the dauer-constitutive phenotypes of sdf-9 mutants were greatly enhanced by cholesterol deprivation. Epistasis analyses, together with the relationship between sdf-9 mutations and daf-9 expression, suggested that SDF-9 increases the activity of DAF-9 or helps the execution of the DAF-9 function. SDF-9 was expressed in two head cells in which DAF-9 is expressed. By their position and by genetic mosaic experiments, we identified these cells as XXXL/R cells, which are known as embryonic hypodermal cells and whose function at later stages is unknown. Killing of the sdf-9-expressing cells in the wild-type first-stage larva induced formation of the dauer-like larva. Since this study on SDF-9 and former studies on DAF-9 showed that the functions of these proteins are related to those of steroids, XXXL/R cells seem to play a key role in the metabolism or function of a steroid hormone(s)that acts in dauer regulation.
- Published
- 2003
9. Mutations Affecting Nerve Attachment of Caenorhabditis elegans
- Author
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Go Shioi, Shin Takagi, Michinari Shoji, Isao Katsura, Hajime Fujisawa, Takeshi Ishihara, and Masashi Nakamura
- Subjects
Genetics ,Mutation ,animal structures ,genetic structures ,Muscles ,Mutant ,Chromosome Mapping ,Biology ,biology.organism_classification ,medicine.disease_cause ,Phenotype ,Green fluorescent protein ,Larva ,Ventral nerve cord ,Muscle attachment ,medicine ,Animals ,Caenorhabditis elegans ,Gene ,Genes, Helminth ,Research Article - Abstract
Using a pan-neuronal GFP marker, a morphological screen was performed to detect Caenorhabditis elegans larval lethal mutants with severely disorganized major nerve cords. We recovered and characterized 21 mutants that displayed displacement or detachment of the ventral nerve cord from the body wall (Ven: ventral cord abnormal). Six mutations defined three novel genetic loci: ven-1, ven-2, and ven-3. Fifteen mutations proved to be alleles of previously identified muscle attachment/positioning genes, mup-4, mua-1, mua-5, and mua-6. All the mutants also displayed muscle attachment/positioning defects characteristic of mua/mup mutants. The pan-neuronal GFP marker also revealed that mutants of other mua/mup loci, such as mup-1, mup-2, and mua-2, exhibited the Ven defect. The hypodermis, the excretory canal, and the gonad were morphologically abnormal in some of the mutants. The pleiotropic nature of the defects indicates that ven and mua/mup genes are required generally for the maintenance of attachment of tissues to the body wall in C. elegans.
- Published
- 2001
10. The conserved nuclear receptor Ftz-F1 is required for embryogenesis, moulting and reproduction in Caenorhabditis elegans
- Author
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Isao Katsura, Takeshi Ishihara, Yuji Kohara, Susumu Hirose, Marek Jindra, and Masako Asahina
- Subjects
Genetics ,animal structures ,Sexual differentiation ,biology ,fungi ,Cell Biology ,In situ hybridization ,biology.organism_classification ,Nuclear receptor ,RNA interference ,Moulting ,Gene ,Transcription factor ,Caenorhabditis elegans - Abstract
Background: Nuclear receptors are essential players in the development of all metazoans. The nematode Caenorhabditis elegans possesses more than 200 putative nuclear receptor genes, several times more than the number known in any other organism. Very few of these transcription factors are conserved with components of the steroid response pathways in vertebrates and arthropods. Ftz-F1, one of the evolutionarily oldest nuclear receptor types, is required for steroidogenesis and sexual differentiation in mice and for segmentation and metamorphosis in Drosophila. Results: We employed two complementary approaches, direct mutagenesis and RNA interference, to explore the role of nhr-25 ,a C. elegans ortholog of Ftz-F1. Deletion mutants show that nhr-25 is essential for embryogenesis. RNA interference reveals additional requirements throughout the postembryonic life, namely in moulting and differentiation of the gonad and vulva. All these defects are consistent with the nhr-25 expression pattern, determined by in situ hybridization and GFP reporter activity. Conclusions: Our data link the C. elegans Ftz-F1 ortholog with a number of developmental processes. Significantly, its role in the periodical replacement of cuticle (moulting) appears to be evolutionarily shared with insects and thus supports the monophyletic origin of moulting.
- Published
- 2000
11. UNC-4/UNC-37-dependent repression of motor neuron-specific genes controls synaptic choice in Caenorhabditis elegans
- Author
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James Y.-J. Meir, David M. Miller, Monica Driscoll, Isao Katsura, Takeshi Ishihara, Angela R. Winnier, Nektarios Tavernarakis, and Jennifer M. Ross
- Subjects
Transcription, Genetic ,Molecular Sequence Data ,Mutant ,Muscle Proteins ,Repressor ,macromolecular substances ,Biology ,Mice ,Genetics ,medicine ,Animals ,Missense mutation ,Amino Acid Sequence ,Caenorhabditis elegans ,Caenorhabditis elegans Proteins ,Psychological repression ,Gene ,Conserved Sequence ,Homeodomain Proteins ,Motor Neurons ,Binding Sites ,Sequence Homology, Amino Acid ,fungi ,Nuclear Proteins ,Helminth Proteins ,Motor neuron ,biology.organism_classification ,Rats ,Cell biology ,Repressor Proteins ,medicine.anatomical_structure ,Amino Acid Substitution ,Gene Expression Regulation ,nervous system ,Synapses ,Corepressor ,Research Paper ,Transcription Factors ,Developmental Biology - Abstract
The UNC-4 homeoprotein and the Groucho-like corepressor UNC-37 specify synaptic choice in the Caenorhabditis elegans motor neuron circuit. In unc-4 mutants, VA motor neurons are miswired with inputs from interneurons normally reserved for their lineal sisters, the VB motor neurons. Here we show that UNC-4 and UNC-37 function together in VA motor neurons to repress VB-specific genes and that this activity depends on physical contact between UNC-37 and a conserved Engrailed-like repressor domain (eh1) in UNC-4. Missense mutations in the UNC-4 eh1 domain disrupt interactions between UNC-4 and UNC-37 and result in the loss of UNC-4-dependent repressor activity in vivo. A compensatory amino acid substitution in UNC-37 suppresses specific unc-4 alleles by restoring physical interactions with UNC-4 as well as UNC-4-dependent repression of VB-specific genes. We propose that repression of VB-specific genes by UNC-4 and UNC-37 is necessary for the creation of wild-type inputs to VA motor neurons. The existence of mammalian homologs of UNC-4 and UNC-37 indicates that a similar mechanism could regulate synaptic choice in the vertebrate spinal cord.
- Published
- 1999
12. An ion channel of the degenerin/epithelial sodium channel superfamily controls the defecation rhythm in Caenorhabditis elegans
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Tosikazu Amano, Takeshi Ishihara, Minoru Kawakami, Isao Katsura, Kazunori Kondo, and Masaya Take-uchi
- Subjects
Activity Cycles ,Epithelial sodium channel ,Green Fluorescent Proteins ,Molecular Sequence Data ,Mutant ,Dauer larva ,Biology ,medicine.disease_cause ,Polymerase Chain Reaction ,Ion Channels ,Sodium Channels ,Fluorides ,Genes, Reporter ,medicine ,Animals ,Amino Acid Sequence ,Cloning, Molecular ,Caenorhabditis elegans ,Defecation ,Genes, Helminth ,DNA Primers ,Ultradian rhythm ,Genetics ,Mutation ,Multidisciplinary ,Base Sequence ,Sequence Homology, Amino Acid ,Sodium channel ,fungi ,Biological Sciences ,biology.organism_classification ,Intestines ,Luminescent Proteins ,Phenotype ,Defecation rhythm - Abstract
Ultradian rhythms are widespread phenomena found in various biological organisms. A typical example is the defecation behavior of the nematode Caenorhabditis elegans, which repeats at about 45-sec intervals. To elucidate the mechanism, we studied flr-1 mutants, which show very short defecation cycle periods. The mutations also affect some food-related functions, including growth rate, the expulsion step of defecation behavior, and the regulation of the dauer larva (a nonfeeding, special third-stage larva) formation in the unc-3 (Olf-1/EBF homolog) background. The flr-1 gene encodes a novel ion channel belonging to the DEG/ENaC ( C. elegans degenerin and mammalian epithelial sodium channel) superfamily. A flr-1 ∷GFP (green fluorescent protein) fusion gene that can rescue the flr-1 mutant phenotypes is expressed only in the intestine from embryos to adults. These results suggest that FLR-1 may be a component of an intestinal regulatory system that controls the defecation rhythm as well as other functions.
- Published
- 1998
13. Ultradian rhythm in the intestine of Caenorhabditis elegans is controlled by the C-terminal region of the FLR-1 ion channel and the hydrophobic domain of the FLR-4 protein kinase
- Author
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Yuri, Kobayashi, Koutarou D, Kimura, and Isao, Katsura
- Subjects
Binding Sites ,Microscopy, Confocal ,Cell Membrane ,Green Fluorescent Proteins ,Protein Serine-Threonine Kinases ,Sodium Channels ,Circadian Rhythm ,Animals, Genetically Modified ,Microscopy, Fluorescence ,Mutation ,Animals ,Intestinal Mucosa ,Caenorhabditis elegans ,Caenorhabditis elegans Proteins ,Protein Kinases - Abstract
Defecation behavior in Caenorhabditis elegans is driven by an endogenous ultradian clock in the intestine. Its periods are positively regulated by FLR-1, an ion channel of the epithelial sodium channel/degenerin superfamily, and FLR-4, a protein kinase with a hydrophobic domain at the carboxyl terminus. FLR-1 has many putative phosphorylation sites in the C-terminal intracellular region. This structure implies that the periods may be regulated by the phosphorylation of FLR-1 by FLR-4, but it remains to be clarified. Here, we show that a truncated FLR-1 lacking the C-terminal intracellular region resulted in longer periods, suggesting that this region is involved in the negative regulation of defecation cycle periods. Contrary to our expectation, FLR-4 was still necessary for the function of the truncated FLR-1. Furthermore, FLR-4 containing a kinase-dead mutation or lacking the whole kinase domain was sufficient for normal defecation cycle periods. FLR-4 was necessary for the stable expression of FLR-1::GFP, and its hydrophobic domain was sufficient also for this function. FLR-1 and FLR-4 are often colocalized in the plasma membrane. These data showed an unexpected role of FLR-4: its hydrophobic domain stabilizes the FLR-1 ion channel, a key regulator of defecation cycle periods in the intestine.
- Published
- 2011
14. Behavioral choice between conflicting alternatives is regulated by a receptor guanylyl cyclase, GCY-28, and a receptor tyrosine kinase, SCD-2, in AIA interneurons of Caenorhabditis elegans
- Author
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Takashi Tabata, Yuta Yamamoto, Takaaki Hirotsu, Yuichi Iino, Yoichi Shinkai, Takashi Murayama, Daisuke D. Ikeda, Isao Katsura, Makoto Tsunozaki, Takeshi Ishihara, Cornelia I. Bargmann, and Manabi Fujiwara
- Subjects
Behavior, Animal ,General Neuroscience ,Mutant ,Membrane Proteins ,Receptor Protein-Tyrosine Kinases ,Sensory system ,Articles ,Biology ,Protein-Tyrosine Kinases ,biology.organism_classification ,Phenotype ,Choice Behavior ,Receptor tyrosine kinase ,Receptors, Guanylate Cyclase-Coupled ,Guanylate Cyclase ,Interneurons ,biology.protein ,Animals ,Cyclic nucleotide-gated ion channel ,Caenorhabditis elegans ,Caenorhabditis elegans Proteins ,Neuroscience ,Sensory cue ,Genetic screen - Abstract
Animals facing conflicting sensory cues make a behavioral choice between competing alternatives through integration of the sensory cues. Here, we performed a genetic screen to identify genes important for the sensory integration of two conflicting cues, the attractive odorant diacetyl and the aversive stimulus Cu2+, and found that the membrane-bound guanylyl cyclase GCY-28 and the receptor tyrosine kinase SCD-2 regulate the behavioral choice between these alternatives inCaenorhabditis elegans. Thegcy-28mutants andscd-2mutants show an abnormal bias in the behavioral choice between the cues, although their responses to each individual cue are similar to those in wild-type animals. Mutants in a gene encoding a cyclic nucleotide gated ion channel,cng-1, also exhibit the defect in sensory integration. Molecular genetic analyses suggested that GCY-28 and SCD-2 regulate sensory integration in AIA interneurons, where the conflicting sensory cues may converge. Genetic ablation or hyperpolarization of AIA interneurons showed nearly the same phenotype asgcy-28orscd-2mutants in the sensory integration, although this did not affect the sensory response to each individual cue. Ingcy-28orscd-2mutants, activation of AIA interneurons is sufficient to restore normal sensory integration. These results suggest that the activity of AIA interneurons regulates the behavioral choice between the alternatives. We propose that GCY-28 and SCD-2 regulate sensory integration by modulating the activity of AIA interneurons.
- Published
- 2011
15. In search of new mutants in cell-signaling systems of the nematodeCaenorhabditis elegans
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Isao Katsura
- Subjects
Cell signaling ,Mutant ,Drug Resistance ,Plant Science ,Biology ,medicine.disease_cause ,Morphogenesis ,Genetics ,medicine ,Animals ,Myoblast migration ,Caenorhabditis elegans ,Gene ,Genes, Helminth ,Mutation ,General Medicine ,biology.organism_classification ,Phenotype ,Mutagenesis ,Larva ,Insect Science ,Sodium Fluoride ,Epistasis ,Genes, Lethal ,Animal Science and Zoology ,Signal Transduction - Abstract
Development of multicellular organisms is controlled mainly by cell-signaling systems. In this review I first discuss methods of genetic analysis and properties of mutants of cell-signaling systems in general and in the nematode C. elegans. Then, I describe two of our approaches to isolating new mutants in cell-signaling of C. elegans. The first approach is to select for mutants that have the same visible phenotype as those in known cell-signaling genes. In a survey of larval lethal mutations we found that there are quite a few mutants in which the inner surface of the body wall is detached from the outer surface of the intestine. Some of them map in genes that are known to act in cell-signaling systems in vulval induction or sex myoblast migration, which are not essential to the growth and survival of C. elegans. Therefore, we think many of the mutations of the above phenotype disrupt cell-signaling in an unidentified essential function, and also cell-signaling in the non-essential functions. The second approach is to isolate mutants resistant to a drug expected to disturb cell-signaling. As the drug we have chosen sodium fluoride, which depletes calcium ion, activates G-proteins and inactivates some phosphatases. The mutants are grouped into two classes (three and two genes, respectively) according to degree of fluoride-resistance and growth rate of larvae. Although there is so far no direct evidence that these mutants are related to cell-signaling, they show complex epistasis that can be explained by a model consisting of a cell-signaling pathway.
- Published
- 1993
16. Enhancement of Odor Avoidance Regulated by Dopamine Signaling in Caenorhabditis elegans
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Kosuke Fujita, Koutarou D. Kimura, and Isao Katsura
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Dopamine ,Sensory system ,Stimulus (physiology) ,Biology ,Gene Knockout Techniques ,medicine ,Avoidance Learning ,Animals ,Habituation ,Receptor ,Caenorhabditis elegans ,Caenorhabditis elegans Proteins ,Receptors, Dopamine D2 ,General Neuroscience ,Articles ,1-Octanol ,Ketones ,biology.organism_classification ,Odor ,Dopamine receptor ,Odorants ,Neuroscience ,medicine.drug ,Signal Transduction - Abstract
The enhancement of sensory responses after prior exposure to a stimulus is a fundamental mechanism of neural function in animals. Its molecular basis, however, has not been studied in as much depth as the reduction of sensory responses, such as adaptation or habituation. We report here that the avoidance behavior of the nematodeCaenorhabditis elegansin response to repellent odors (2-nonanone or 1-octanol) is enhanced rather than reduced after preexposure to the odors. This enhancement effect of preexposure was maintained for at least 1 h after the conditioning. The enhancement of 2-nonanone avoidance was not dependent on the presence or absence of food during conditioning, which generally functions as a strong positive or negative unconditioned stimulus in the animals. These results suggest that the enhancement is acquired as a type of nonassociative learning. In addition, genetic and pharmacological analyses revealed that the enhancement of 2-nonanone avoidance requires dopamine signaling via D2-like dopamine receptor DOP-3, which functions in a pair of RIC interneurons to regulate the enhancement. Because dopamine signaling has been tightly linked with food-related information to modulate various behaviors ofC. elegans, it may play different role in the regulation of the enhancement of 2-nonanone avoidance. Thus, our data suggest a new genetic and pharmacological paradigm for nonassociative enhancement of neural responses that is regulated by dopamine signaling.
- Published
- 2010
17. FLR-2, the glycoprotein hormone alpha subunit, is involved in the neural control of intestinal functions in Caenorhabditis elegans
- Author
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Keiko Gengyo-Ando, Koutarou D. Kimura, Akane Oishi, Akiko Mohri-Shiomi, Takeshi Ishihara, Isao Katsura, and Shohei Mitani
- Subjects
DNA, Complementary ,Recombinant Fusion Proteins ,Mutant ,Green Fluorescent Proteins ,Molecular Sequence Data ,Life Expectancy ,Genetics ,Neural control ,Escherichia coli ,Animals ,Amino Acid Sequence ,Cloning, Molecular ,Caenorhabditis elegans ,Caenorhabditis elegans Proteins ,Gene ,G alpha subunit ,chemistry.chemical_classification ,Neurons ,biology ,Sequence Homology, Amino Acid ,Pigmentation ,Cell Biology ,Sequence Analysis, DNA ,biology.organism_classification ,Molecular biology ,Cell biology ,Intestines ,Secretory protein ,chemistry ,Microscopy, Fluorescence ,Glycoprotein Hormones, alpha Subunit ,Host-Pathogen Interactions ,Mutation ,RNA Interference ,Glycoprotein ,Carrier Proteins ,Hormone ,Protein Binding - Abstract
The intestine plays an essential role in organism-wide regulatory networks in both vertebrates and invertebrates. In Caenorhabditis elegans, class 1 flr genes (flr-1, flr-3 and flr-4) act in the intestine and control growth rates and defecation cycle periods, while class 2 flr genes (flr-2, flr-5, flr-6 and flr-7) are characterized by mutations that suppress the slow growth of class 1 flr mutants. This study revealed that flr-2 gene controls antibacterial defense and intestinal color, confirming that flr-2 regulates intestinal functions. flr-2 encoded the only glycoprotein hormone alpha subunit in C. elegans and was expressed in certain neurons. Furthermore, FLR-2 bound to another secretory protein GHI-1, which belongs to a family of lipid- and lipopolysaccharide-binding proteins. A ghi-1 deletion mutation partially suppressed the short defecation cycle periods of class 1 flr mutants, and this effect was enhanced by flr-2 mutations. Thus, FLR-2 acts as a signaling molecule for the neural control of intestinal functions, which is achieved in a functional network involving class 1 and class 2 flr genes as well as ghi-1. These results are informative to studies of glycoprotein hormone signaling in higher animals.
- Published
- 2009
18. Left-right olfactory asymmetry results from antagonistic functions of voltage-activated calcium channels and the Raw repeat protein OLRN-1 in C. elegans
- Author
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Yasunori Saheki, Miri K. VanHoven, Sarah L. Bauer Huang, Ichiro Torayama, Alexander M. van der Linden, Isao Katsura, Piali Sengupta, Takeshi Ishihara, and Cornelia I. Bargmann
- Subjects
Sensory Receptor Cells ,MAP Kinase Signaling System ,Cellular differentiation ,Muscle Proteins ,chemistry.chemical_element ,Calcium ,Biology ,Nervous System ,Connexins ,Functional Laterality ,lcsh:RC346-429 ,03 medical and health sciences ,0302 clinical medicine ,Developmental Neuroscience ,Ca2+/calmodulin-dependent protein kinase ,Claudin-1 ,medicine ,Animals ,Drosophila Proteins ,Calcium Signaling ,Caenorhabditis elegans ,Caenorhabditis elegans Proteins ,lcsh:Neurology. Diseases of the nervous system ,030304 developmental biology ,Calcium signaling ,0303 health sciences ,Voltage-dependent calcium channel ,Calcium channel ,Gene Expression Regulation, Developmental ,Membrane Proteins ,Cell Differentiation ,Olfactory Pathways ,biology.organism_classification ,Cell biology ,Cytoskeletal Proteins ,medicine.anatomical_structure ,chemistry ,Calcium Channels ,Neuron ,Calcium-Calmodulin-Dependent Protein Kinase Type 2 ,030217 neurology & neurosurgery ,Research Article - Abstract
Background The left and right AWC olfactory neurons in Caenorhabditis elegans differ in their functions and in their expression of chemosensory receptor genes; in each animal, one AWC randomly takes on one identity, designated AWCOFF, and the contralateral AWC becomes AWCON. Signaling between AWC neurons induces left-right asymmetry through a gap junction network and a claudin-related protein, which inhibit a calcium-regulated MAP kinase pathway in the neuron that becomes AWCON. Results We show here that the asymmetry gene olrn-1 acts downstream of the gap junction and claudin genes to inhibit the calcium-MAP kinase pathway in AWCON. OLRN-1, a protein with potential membrane-association domains, is related to the Drosophila Raw protein, a negative regulator of JNK mitogen-activated protein (MAP) kinase signaling. olrn-1 opposes the action of two voltage-activated calcium channel homologs, unc-2 (CaV2) and egl-19 (CaV1), which act together to stimulate the calcium/calmodulin-dependent kinase CaMKII and the MAP kinase pathway. Calcium channel activity is essential in AWCOFF, and the two AWC neurons coordinate left-right asymmetry using signals from the calcium channels and signals from olrn-1. Conclusion olrn-1 and voltage-activated calcium channels are mediators and targets of AWC signaling that act at the transition between a multicellular signaling network and cell-autonomous execution of the decision. We suggest that the asymmetry decision in AWC results from the intercellular coupling of voltage-regulated channels, whose cross-regulation generates distinct calcium signals in the left and right AWC neurons. The interpretation of these signals by the kinase cascade initiates the sustained difference between the two cells.
- Published
- 2007
19. IFT-81 and IFT-74 are required for intraflagellar transport in C. elegans
- Author
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Tetsuo, Kobayashi, Keiko, Gengyo-Ando, Takeshi, Ishihara, Isao, Katsura, and Shohei, Mitani
- Subjects
Animals, Genetically Modified ,Phenotype ,Flagella ,Chemotaxis ,Mutation ,Animals ,Biological Transport, Active ,Cilia ,Neurons, Afferent ,Caenorhabditis elegans ,Caenorhabditis elegans Proteins ,Carrier Proteins ,Genes, Helminth - Abstract
Intraflagellar transport (IFT) is essential machinery for biogenesis and maintenance of cilia in many eukaryotic and prokaryotic cells. A large number of polypeptides are known to be involved in IFT, but the physiological role of each component is not fully elucidated. Here, we identified a C. elegans orthologue of a Chlamydomonas reinhardtii IFT component, IFT-81, and found that its loss-of-function mutants show an unusual behavioral property and small body size. IFT-81 is expressed in sensory neurons, and localized at the base of cilia. The similar phenotypes with ift-81 mutants were also observed in several IFT mutants, suggesting these defects are caused by inability of IFT. We also demonstrated that IFT-81 interacts and co-localizes with IFT-74, which is another putative component of IFT. The ift-74 loss-of-function mutants showed phenocopies with ift-81 mutants, suggesting IFT-81 and IFT-74 play comparable functions. Moreover, ift-81 and ift-74 mutants similarly exhibited weak anomalies in cilia formation and obvious disruptions of transport in mature cilia. Thus, we conclude that IFT-81 and IFT-74 coordinately act in IFT in C. elegans sensory cilia.
- Published
- 2007
20. Multidrug resistance-associated protein MRP-1 regulates dauer diapause by its export activity in Caenorhabditis elegans
- Author
-
Tomoko Yabe, Takeshi Ishihara, Isao Katsura, Tatsuhiko Furukawa, and Norio Suzuki
- Subjects
Recombinant Fusion Proteins ,Mutant ,ATP-binding cassette transporter ,Biology ,Dauer larva ,Green fluorescent protein ,stomatognathic system ,Genes, Reporter ,Animals ,Humans ,Protein Isoforms ,ATP Binding Cassette Transporter, Subfamily B, Member 1 ,Caenorhabditis elegans ,Molecular Biology ,Gene ,Genetics ,fungi ,Sequence Analysis, DNA ,biology.organism_classification ,Phenotype ,Cell biology ,Protein Transport ,Larva ,Cancer cell ,Mutation ,Developmental Biology - Abstract
Multidrug resistance-associated proteins (MRPs), when overexpressed, confer drug resistance to cancer cells by exporting anti-cancer agents through the cell membrane, but their role in animal development has not been elucidated. Here we show that an MRP homolog regulates larval development in the nematode Caenorhabditis elegans. C. elegans forms a special third-stage larva called a dauer larva under conditions inappropriate for growth. By contrast, we found that mutants in mrp-1, an MRP homolog gene, form dauer larvae even under conditions appropriate for growth, in the background of certain mutations that partially block the insulin signaling pathway. A functional mrp-1::GFP gene was shown to be expressed in many tissues, and the wild-type mrp-1 gene must be expressed in multiple tissues for a wild-type phenotype. Human MRP1 could substitute for C. elegans MRP-1 in dauer larva regulation, and an inhibitor of the human MRP1 transport activity impaired this function, showing that export activity is required for normal dauer larva regulation. Epistasis studies revealed that MRP-1 acts in neither the TGF-β nor the cGMP signaling pathway. mrp-1 mutations enhanced the dauer-constitutive phenotype of mutants in the insulin signaling pathway more strongly than that in other pathways. Thus, MRP-1, through its export activity, supports the induction of the normal (non-dauer) life cycle by the insulin signaling pathway.
- Published
- 2005
21. FLR-4, a Novel Serine/Threonine Protein Kinase, Regulates Defecation Rhythm in Caenorhabditis elegans
- Author
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Masaya Take-uchi, Koutarou D. Kimura, Isao Katsura, Yuri Kobayashi, and Takeshi Ishihara
- Subjects
Time Factors ,Mutant ,Receptors, Cytoplasmic and Nuclear ,Serine threonine protein kinase ,Serine ,Genes, Reporter ,Inositol 1,4,5-Trisphosphate Receptors ,Tissue Distribution ,Transgenes ,Cloning, Molecular ,Intestinal Mucosa ,Defecation ,Caenorhabditis elegans ,Neurons ,biology ,Muscles ,Temperature ,Gene Expression Regulation, Developmental ,Articles ,Circadian Rhythm ,Intestines ,Phenotype ,Pharyngeal Muscles ,DNA, Complementary ,Genotype ,Recombinant Fusion Proteins ,Green Fluorescent Proteins ,Molecular Sequence Data ,Mutation, Missense ,Protein Serine-Threonine Kinases ,Oscillometry ,Animals ,Amino Acid Sequence ,Protein kinase A ,Caenorhabditis elegans Proteins ,Molecular Biology ,Alleles ,Models, Genetic ,Sequence Homology, Amino Acid ,Lasers ,Cell Biology ,Sequence Analysis, DNA ,Inositol trisphosphate receptor ,biology.organism_classification ,Molecular biology ,Protein Structure, Tertiary ,Protein kinase domain ,Mutation ,Defecation rhythm ,Calcium Channels - Abstract
The defecation behavior of the nematode Caenorhabditis elegans is controlled by a 45-s ultradian rhythm. An essential component of the clock that regulates the rhythm is the inositol trisphosphate receptor in the intestine, but other components remain to be discovered. Here, we show that the flr-4 gene, whose mutants exhibit very short defecation cycle periods, encodes a novel serine/threonine protein kinase with a carboxyl terminal hydrophobic region. The expression of functional flr-4::GFP was detected in the intestine, part of pharyngeal muscles and a pair of neurons, but expression of flr-4 in the intestine was sufficient for the wild-type phenotype. Furthermore, laser killing of the flr-4–expressing neurons did not change the defecation phenotypes of wild-type and flr-4 mutant animals. Temperature-shift experiments with a temperature-sensitive flr-4 mutant suggested that FLR-4 acts in a cell-functional rather than developmental aspect in the regulation of defecation rhythms. The function of FLR-4 was impaired by missense mutations in the kinase domain and near the hydrophobic region, where the latter allele seemed to be a weak antimorph. Thus, a novel protein kinase with a unique structural feature acts in the intestine to increase the length of defecation cycle periods.
- Published
- 2005
22. Negative regulation and gain control of sensory neurons by the C. elegans calcineurin TAX-6
- Author
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Atsushi Kuhara, Hitoshi Inada, Ikue Mori, and Isao Katsura
- Subjects
Neuroscience(all) ,Recombinant Fusion Proteins ,Mutant ,Molecular Sequence Data ,TRPV Cation Channels ,Sensory system ,Nerve Tissue Proteins ,Biology ,medicine.disease_cause ,Models, Biological ,Ion Channels ,Animals, Genetically Modified ,Pentanols ,Transient Receptor Potential Channels ,medicine ,Animals ,Humans ,Thermosensing ,Amino Acid Sequence ,Neurons, Afferent ,Caenorhabditis elegans ,Caenorhabditis elegans Proteins ,Mutation ,General Neuroscience ,Calcineurin ,Osmolar Concentration ,Olfactory fatigue ,Phenotype ,Sensory neuron ,Smell ,Protein Subunits ,medicine.anatomical_structure ,Signal transduction ,Neuroscience ,Sequence Alignment ,Locomotion ,Signal Transduction - Abstract
Animals sense and adapt to variable environments by regulating appropriate sensory signal transduction pathways. Here, we show that calcineurin plays a key role in regulating the gain of sensory neuron responsiveness across multiple modalities. C. elegans animals bearing a loss-of-function mutation in TAX-6, a calcineurin A subunit, exhibit pleiotropic abnormalities, including many aberrant sensory behaviors. The tax-6 mutant defect in thermosensation is consistent with hyperactivation of the AFD thermosensory neurons. Conversely, constitutive activation of TAX-6 causes a behavioral phenotype consistent with inactivation of AFD neurons. In olfactory neurons, the impaired olfactory response of tax-6 mutants to an AWC-sensed odorant is caused by hyperadaptation, which is suppressible by a mutation causing defective olfactory adaptation. Taken together, our results suggest that stimulus-evoked calcium entry activates calcineurin, which in turn negatively regulates multiple aspects of sensory signaling.
- Published
- 2002
23. A novel WD40 protein, CHE-2, acts cell-autonomously in the formation of C. elegans sensory cilia
- Author
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Manabi Fujiwara, Isao Katsura, and Takeshi Ishihara
- Subjects
Repetitive Sequences, Amino Acid ,Protein family ,Mutant ,Molecular Sequence Data ,Sensory system ,Green fluorescent protein ,medicine ,Animals ,Amino Acid Sequence ,Cilia ,Neurons, Afferent ,Caenorhabditis elegans ,Molecular Biology ,Regulation of gene expression ,Genetics ,biology ,Base Sequence ,Cilium ,Gene Expression Regulation, Developmental ,Sense Organs ,Helminth Proteins ,biology.organism_classification ,Sensory neuron ,Cell biology ,medicine.anatomical_structure ,Larva ,Mutation ,Developmental Biology - Abstract
To elucidate the mechanism of sensory cilium formation, we analyzed mutants in the Caenorhabditis elegans che-2 gene. These mutants have extremely short cilia with an abnormal posterior projection, and show defects in behaviors that are mediated by ciliated sensory neurons. The che-2 gene encodes a new member of the WD40 protein family, suggesting that it acts in protein-protein interaction. Analysis of mutation sites showed that both the amino-terminal WD40 repeats and the carboxyl-terminal non-WD40 domain are necessary for the CHE-2 function. CHE-2-tagged green fluorescent protein is localized at the cilia of almost all the ciliated sensory neurons. Expression of che-2 in a subset of sensory neurons of a che-2 mutant by using a heterologous promoter resulted in restoration of the functions and cilium morphology of only the che-2-expressing neurons. Thus, che-2 acts cell-autonomously. This technique can be used in the future for determining the function of each type of che-2-expressing sensory neuron. Using green fluorescent protein, we found that the extension of cilia in wild-type animals took place at the late embryonic stage, whereas the cilia of che-2 mutant animals remained always short during development. Hence, the abnormal posterior projection is due to the inability of cilia to extend, rather than degeneration of cilia once correctly formed. Expression of che-2 in a che-2 mutant under a heat shock promoter showed that the extension of cilia, surprisingly, can occur even at the adult stage, and that such cilia can function apparently normally in behavior.
- Published
- 1999
24. hch-1, a gene required for normal hatching and normal migration of a neuroblast in C. elegans, encodes a protein related to TOLLOID and BMP-1
- Author
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Ryuichi Hishida, Isao Katsura, Takeshi Ishihara, and Kazunori Kondo
- Subjects
animal structures ,Tolloid-Like Metalloproteinases ,Cellular differentiation ,Molecular Sequence Data ,Bone morphogenetic protein ,General Biochemistry, Genetics and Molecular Biology ,Bone morphogenetic protein 1 ,Bone Morphogenetic Protein 1 ,Evolution, Molecular ,Neuroblast ,Species Specificity ,Morphogenesis ,Animals ,Drosophila Proteins ,Amino Acid Sequence ,RNA, Messenger ,Caenorhabditis elegans ,Caenorhabditis elegans Proteins ,Molecular Biology ,Genes, Helminth ,Ovum ,Genetics ,Mammals ,General Immunology and Microbiology ,biology ,Base Sequence ,Sequence Homology, Amino Acid ,General Neuroscience ,Metalloendopeptidases ,Proteins ,Cell Differentiation ,Helminth Proteins ,DNA, Helminth ,CUB domain ,biology.organism_classification ,Mutagenesis, Insertional ,Drosophila melanogaster ,Gene Expression Regulation ,Insect Hormones ,Sea Urchins ,embryonic structures ,Bone Morphogenetic Proteins ,Astacin ,RNA, Helminth ,Sequence Alignment ,Drosophila Protein ,Research Article - Abstract
Proteins of the tolloid/bone morphogenetic protein (BMP)-1 family play important roles in the differentiation of cell fates. Among those proteins are BMP-1, which plays a role in cartilage and bone formation in mammals, the TOLLOID protein, which is required for the establishment of the dorsoventral axis of Drosophila embryos and BP10/SpAN, which are thought to act in the morphogenesis of sea urchins. These proteins have some properties in common. First, they contain the astacin metalloprotease domain, the CUB domain and the epidermal growth factor-like domain. Second, they are expressed in embryos at stages expected for their role in cell differentiation. Third, at least BMP-1 and TOLLOID are thought to interact with proteins of the transforming growth factor-beta family. We report that the hch-1 gene of the nematode Caenorhabditis elegans encodes a tolloid/BMP-1 family protein. The protein has the characteristic domains common to the tolloid/ BMP-1 family. Like other members of the family, it is expressed in embryos. However, the phenotype of hch-1 mutants shows that it is required for normal hatching and normal migration of a post-embryonic neuroblast. Furthermore, in spite of its expression in embryogenesis, it is not required for the viability of embryos. These results show new functions of the tolloid/BMP-1 family proteins and give insight into their evolution.
- Published
- 1996
25. Isolation, characterization and epistasis of fluoride-resistant mutants of Caenorhabditis elegans
- Author
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Isao Katsura, Koji Kondo, M. Kawakami, Takeshi Ishihara, and T. Amano
- Subjects
Genetic Markers ,Male ,Heterozygote ,Phosphatase ,Mutant ,Drug Resistance ,Genes, Recessive ,Biology ,Investigations ,medicine.disease_cause ,chemistry.chemical_compound ,Sodium fluoride ,Genetics ,medicine ,Animals ,Caenorhabditis elegans ,Gene ,Crosses, Genetic ,Mutation ,Reproduction ,Chromosome Mapping ,biology.organism_classification ,Molecular biology ,Phenotype ,chemistry ,Epistasis ,Sodium Fluoride ,Female ,Fluoride ,DNA Damage - Abstract
We have isolated 13 fluoride-resistant mutants of the nematode Caenorhabditis elegans. All the mutations are recessive and mapped to five genes. Mutants in three of the genes (class 1 genes: flr-1 X, flr-3 IV, and flr-4 X) are resistant to 400 micrograms/ml NaF. Furthermore, they grow twice as slowly as and have smaller brood size than wild-type worms even in the absence of fluoride ion. In contrast, mutants in the other two genes (class 2 genes: flr-2 V and flr-5 V) are only partially resistant to 400 micrograms/ml NaF, and they have almost normal growth rates and brood sizes in the absence of fluoride ion. Studies on the phenotypes of double mutants showed that class 2 mutations are epistatic to class 1 mutations concerning growth rate and brood size but hypostatic with respect to fluoride resistance. We propose two models that can explain the epistasis. Since fluoride ion depletes calcium ion, inhibits some protein phosphatases and activates trimeric G-proteins, studies on these mutants may lead to discovery of a new signal transduction system that controls the growth of C. elegans.
- Published
- 1994
26. 野生由来マウス系統を使った行動の遺伝解析 (特集:総研大の脳科学 / Part 2 脳科学の最前線 / 線虫で探る遺伝子と行動)
- Author
-
Isao, KATSURA
- Published
- 2003
27. FLR-4, a novel serine/threonine protein kinase, regulates defecation rhythm in Caenorhabditis elegans.
- Author
-
Masaya, Take-uchi, Yuri, Kobayashi, D, Kimura Koutarou, Takeshi, Ishihara, and Isao, Katsura
- Abstract
The defecation behavior of the nematode Caenorhabditis elegans is controlled by a 45-s ultradian rhythm. An essential component of the clock that regulates the rhythm is the inositol trisphosphate receptor in the intestine, but other components remain to be discovered. Here, we show that the flr-4 gene, whose mutants exhibit very short defecation cycle periods, encodes a novel serine/threonine protein kinase with a carboxyl terminal hydrophobic region. The expression of functional flr-4::GFP was detected in the intestine, part of pharyngeal muscles and a pair of neurons, but expression of flr-4 in the intestine was sufficient for the wild-type phenotype. Furthermore, laser killing of the flr-4-expressing neurons did not change the defecation phenotypes of wild-type and flr-4 mutant animals. Temperature-shift experiments with a temperature-sensitive flr-4 mutant suggested that FLR-4 acts in a cell-functional rather than developmental aspect in the regulation of defecation rhythms. The function of FLR-4 was impaired by missense mutations in the kinase domain and near the hydrophobic region, where the latter allele seemed to be a weak antimorph. Thus, a novel protein kinase with a unique structural feature acts in the intestine to increase the length of defecation cycle periods.
- Published
- 2005
28. Proteins as studied by exchanges of amino acid residues - A basis of protein engineering
- Author
-
Isao Katsura
- Subjects
Biochemistry ,Chemistry ,Protein engineering ,Amino acid residue - Published
- 1987
29. A regulator protein for the length determination of bacteriophage lambda tail
- Author
-
Peter W. Kühl and Isao Katsura
- Subjects
Lysis ,Mutant ,Biology ,Coliphages ,Guanidines ,Bacteriophage ,Gene product ,Viral Proteins ,chemistry.chemical_compound ,Centrifugation, Density Gradient ,Morphogenesis ,Sodium dodecyl sulfate ,Lysogeny ,Polyacrylamide gel electrophoresis ,Genetics ,Molecular mass ,Genetic Complementation Test ,DNA Viruses ,Sodium Dodecyl Sulfate ,General Medicine ,Hydrogen-Ion Concentration ,Chromatography, Ion Exchange ,biology.organism_classification ,Molecular Weight ,Complementation ,Microscopy, Electron ,Genes ,chemistry ,Mutation ,Biophysics ,Electrophoresis, Polyacrylamide Gel - Abstract
Mutants in gene U of phage X produce polytails. Those polytails have a tail fiber and a basal part like normal tails, but their major tubular part is longer than that of normal tails and shows a wide length distribution. We established the morphogenetic pathway of the X tail and found that U gene product (pU) acts throughout the assembly of the major tail protein (pV). Polytails in U- lysate are activated by pU in vitro and form long-tailed phage which are infectious to a small extent. If the formation of the basal part of the tail is blocked, pV (the major tail protein) remains unassembled as long as pU is present in the cell. However, we found that part of pV assembles into giant polytubes of several microns in length in lysates of a double mutant U(about 2.5s) in vitro under extreme conditions. The disks form polytubes efficiently under physiological conditions, but the smaller units do not form polytubes efficiently. The smaller units have in vitro complementation activity with V- lysate. In vitro complementation activities with V-, U-, and Z- lysates are detected in the dialyzed extracts of SDS gel electrophoresis of purified tails. The molecular weights of the polypeptide chains containing those activities are estimated to be 3 1,000, 14,000 and 20,000 daltons, respectively. H- in which both the basal part and pU are absent. pV in purified tails can be dissociated into disks (about 10s) or smaller units
- Published
- 1974
30. Primary structure and transcriptional regulation of rat pepsinogen C gene
- Author
-
Isao Katsura, Takeshi Ishihara, Yoshikazu Ichihara, Kenji Takahashi, Yoshiaki Fujii-Kuriyama, Kazuhiro Sogawa, and T. Hayano
- Subjects
Transcription, Genetic ,Pepsinogen C ,Molecular Sequence Data ,Restriction Mapping ,Biology ,digestive system ,Biochemistry ,Exon ,Complementary DNA ,Genes, Regulator ,Animals ,Coding region ,Amino Acid Sequence ,Southwestern blot ,Molecular Biology ,Gene ,Southern blot ,Base Sequence ,Pepsinogens ,Nucleic acid sequence ,Nucleic Acid Hybridization ,Rats, Inbred Strains ,DNA ,Cell Biology ,Molecular biology ,digestive system diseases ,Rats ,Blotting, Southern ,Genes - Abstract
The entire rat pepsinogen C gene has been isolated from a rat genomic library, using the rat pepsinogen C cDNA as a probe. Southern blot analysis showed that there exists at least two rat pepsinogen C genes. The nucleotide sequences of the coding regions and the 5'- and 3'-flanking regions of one of the rat pepsinogen C genes have been determined. This gene is split into 9 exons interrupted by eight intervening sequences. The 5'-flanking region is similar to that of the human pepsinogen C gene, but only the former has the core sequence of the Sp1 binding site. The amount of transcripts of the rat pepsinogen C genes was found to increase during development, and a similar increase was shown to be induced by injection of hydrocortisone. As a candidate of a factor which regulates the transcription, we found a 25-kDa protein by Southwestern blotting. It binds to a specific site in the 5'-flanking region of the gene only in the presence of Mg2+ ion, and it is present in the nuclear fraction of the gastric mucosa but not of the liver.
- Published
- 1989
31. HEN-1, a Secretory Protein with an LDL Receptor Motif, Regulates Sensory Integration and Learning in Caenorhabditis elegans
- Author
-
Ikue Mori, Yuichi Iino, Isao Katsura, Shohei Mitani, Keiko Gengyo-Ando, Takeshi Ishihara, and Akiko Mohri
- Subjects
Nervous system ,Bodily Secretions ,Mutant ,Amino Acid Motifs ,Sensation ,Sensory system ,Nerve Tissue Proteins ,Nervous System ,General Biochemistry, Genetics and Molecular Biology ,Evolution, Molecular ,Neural Pathways ,medicine ,Animals ,Learning ,Caenorhabditis elegans ,Caenorhabditis elegans Proteins ,Phylogeny ,Homeodomain Proteins ,Neurons ,biology ,Biochemistry, Genetics and Molecular Biology(all) ,Neuropeptides ,Anatomy ,biology.organism_classification ,Cell biology ,Secretory protein ,medicine.anatomical_structure ,Phenotype ,Gene Expression Regulation ,Receptors, LDL ,LDL receptor ,Motif (music) ,Signal Transduction - Abstract
Animals sense many environmental stimuli simultaneously and integrate various sensory signals within the nervous system both to generate proper behavioral responses and also to form relevant memories. HEN-1, a secretory protein with an LDL receptor motif, regulates such processes in Caenorhabditis elegans. The hen-1 mutants show defects in the integration of two sensory signals and in behavioral plasticity by paired stimuli, although their sensation capability seems to be identical to that of the wild-type. The HEN-1 protein is expressed in two pairs of neurons, but expression in other neurons is sufficient for wild-type behavior. In addition, expression of HEN-1 at the adult stage is sufficient. Thus, HEN-1 regulates sensory processing non-cell-autonomously in the mature neuronal circuit.
- Full Text
- View/download PDF
32. Determination of bacteriophage lambda tail length by a protein ruler
- Author
-
Isao Katsura
- Subjects
Genetics ,Mutation ,Multidisciplinary ,Biometry ,biology ,Genes, Viral ,A protein ,Protein engineering ,Viral Tail Proteins ,biology.organism_classification ,medicine.disease_cause ,Lambda ,Styloviridae ,Bacteriophage lambda ,Bacteriophage ,Viral Proteins ,medicine ,Biophysics ,Chromosome Deletion ,Gene - Abstract
How the size and shape of living structures are determined by genetic information is one of the fundamental problems in biology. Here I describe a study in which the size of a biological supramolecular structure was changed in a predictable way by in vitro genetics, with the size both before and after manipulation being exactly determined. I have studied the tail of bacteriophage lambda, whose length is determined by the length of the 'ruler protein', the product of gene H. The length of the tail can be decreased or increased by deleting the middle part of gene H or by forming a small duplication there, and the length of the tail is proportional to the size of the protein. These results can be regarded as a special case of protein engineering, namely supramolecular protein engineering.
- Published
- 1987
33. A clinical approach to brown adipose tissue in the para-aortic area of the human thorax.
- Author
-
Huixing Wei, Seiichi Chiba, Chinatsu Moriwaki, Hirokazu Kitamura, Keisuke Ina, Taishi Aosa, Kenichiro Tomonari, Koro Gotoh, Takayuki Masaki, Isao Katsuragi, Hitoshi Noguchi, Tetsuya Kakuma, Kazuyuki Hamaguchi, Tatsuo Shimada, Yoshihisa Fujikura, and Hirotaka Shibata
- Subjects
Medicine ,Science - Abstract
BACKGROUND:Human thoracic brown adipose tissue (BAT), composed of several subdivisions, is a well-known target organ of many clinical studies; however, the functional contribution of each part of human thoracic BAT remains unknown. The present study analyzed the significance of each part of human thoracic BAT in the association between regional distribution, cellularity, and factors involved in the functional regulation of thoracic BAT. METHODS:We analyzed 1550 healthy adults who underwent medical check-ups by positron-emission tomography and computed tomography (PET-CT) imaging, 8 cadavers, and 78 autopsy cases in an observational study. We first characterized the difference between the mediastinum and the supraclavicular areas using counts of BAT detection and conditions based on PET-CT outcomes. The measurable important area was then subjected to systematic anatomical and immunohistochemical analyses using anti-uncoupling protein 1 (UCP1) antibody to characterize the cellularity in association with age and sex. RESULTS:In PET-CT scanning, the main site of thoracic BAT was the mediastinum rather than the supraclavicular area (P < 0.05). Systemic macroanatomy revealed that the thumb-sized BAT in the posterior mediastinal descending para-aortic area (paBAT) had feeding vessels from the posterior intercostal arteries and veins and sympathetic/parasympathetic innervation from trunks of the sympathetic and vagus nerves, respectively. Immunohistochemical analysis indicated that the paBAT exhibited immunoreactivity for tyrosine hydroxylase and vesicular acetylcholine transporter located in the pericellular nervous fibers and intracellular UCP1. The brown adipose cells of paBAT showed age-dependent decreases in UCP1 expression (P < 0.05), accompanied by a significant increase in vacuole formation, indicating fat accumulation (P < 0.05), from 10 to 37 years of age (P < 0.01). CONCLUSIONS:paBAT may be one of the essential sites for clinical application in BAT study because of its visible anatomy with feeding vessels and sympathetic/parasympathetic innervation functionally affected by outer condition and senescence.
- Published
- 2015
- Full Text
- View/download PDF
34. Spleen-derived interleukin-10 downregulates the severity of high-fat diet-induced non-alcoholic fatty pancreas disease.
- Author
-
Koro Gotoh, Megumi Inoue, Kentaro Shiraishi, Takayuki Masaki, Seiichi Chiba, Kimihiko Mitsutomi, Takanobu Shimasaki, Hisae Ando, Kansuke Fujiwara, Isao Katsuragi, Tetsuya Kakuma, Masataka Seike, Toshiie Sakata, and Hironobu Yoshimatsu
- Subjects
Medicine ,Science - Abstract
Obesity is associated with systemic low-grade inflammation and is a risk factor for non-alcoholic fatty pancreas disease (NAFPD), but the molecular mechanisms of these associations are not clear. Interleukin (IL)-10, a potent anti-inflammatory cytokine, is released during acute pancreatitis and is known to limit inflammatory responses by downregulating the release of proinflammatory mediators. The origin of IL-10 that suppresses pancreatitis has not been investigated. Since obesity is known to reduce expression of proinflammatory cytokines in the spleen, we examined whether spleen-derived IL-10 regulates NAFPD caused by high-fat (HF) diet-induced obesity. The following investigations were performed: 1) IL-10 induction from spleen was examined in male mice fed a HF diet; 2) triglyceride content, expression of pro- and anti-inflammatory cytokines and infiltration of M1 and M2 macrophages were determined to evaluate ectopic fat accumulation and inflammatory responses in the pancreas of splenectomy (SPX)-treated mice fed HF diet; 3) exogenous IL-10 was systemically administered to SPX-treated obese mice and the resulting pathogenesis caused by SPX was assessed; and 4) IL-10 knockout (IL-10KO) mice were treated with SPX and ectopic fat deposition and inflammatory conditions in the pancreas were investigated. Obesity impaired the ability of the spleen to synthesize cytokines, including IL-10. SPX aggravated fat accumulation and inflammatory responses in the pancreas of HF diet-induced obese mice and these effects were inhibited by systemic administration of IL-10. Moreover, SPX had little effect on fat deposition and inflammatory responses in the pancreas of IL-10KO mice. Our findings indicate that obesity reduces IL-10 production by the spleen and that spleen-derived IL-10 may protect against the development of NAFPD.
- Published
- 2012
- Full Text
- View/download PDF
35. Metabotropic Glutamate Receptors.
- Author
-
Dillon, James, Franks, Christopher J., Murray, Caitriona, Edwards, Richard J., Calahorro, Fernando, Takeshi Ishihara, Isao Katsura, Holden-Dye, Lindy, and O'Connor, Vincent
- Subjects
- *
GLUTAMATE receptors , *NEURAL transmission , *CAENORHABDITIS elegans , *OPTOGENETICS , *ELECTROPHYSIOLOGY - Abstract
Glutamatergic neurotransmission is evolutionarily conserved across animal phyla. A major class of glutamate receptors consists of the metabotropic glutamate receptors (mGluRs). In C. elegans, three mGluR genes, mgl-1, mgl-2, and mgl-3, are organized into three subgroups, similar to their mammalian counterparts. Cellular reporters identified expression of the mgls in the nervous system of C. elegans and overlapping expression in the pharyngeal microcircuit that controls pharyngeal muscle activity and feeding behavior. The overlapping expression of mgls within this circuit allowed the investigation of receptor signaling per se and in the context of receptor interactions within a neural network that regulates feeding. We utilized the pharmacological manipulation of neuronally regulated pumping of the pharyngeal muscle in the wild-type and mutants to investigate MGL function. This defined a net mgl-1-dependent inhibition of pharyngeal pumping that is modulated by mgl-3 excitation. Optogenetic activation of the pharyngeal glutamatergic inputs combined with electrophysiological recordings from the isolated pharyngeal preparations provided further evidence for a presynaptic mgl-1-dependent regulation of pharyngeal activity. Analysis of mgl-1, mgl-2, and mgl-3 mutant feeding behavior in the intact organism after acute food removal identified a significant role for mgl-1 in the regulation of an adaptive feeding response. Our data describe the molecular and cellular organization of mgl-1, mgl-2, and mgl-3. Pharmacological analysis identified that, in these paradigms, mgl-1 and mgl-3, but not mgl-2, can modulate the pharyngeal microcircuit. Behavioral analysis identified mgl-1 as a significant determinant of the glutamate-dependent modulation of feeding, further highlighting the significance of mGluRs in complex C. elegans behavior. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
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