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Fossil dinosaur embryos are surprisingly rare, being almost entirely restricted to Upper Cretaceous strata that record the late stages of non-avian dinosaur evolution (1,2). Notable exceptions are the oldest known [...]

Members of the Wnt family are secreted glycoproteins that trigger cellular signals essential for proper development of organisms. Cellular signaling induced by Wnt proteins is involved in diverse developmental processes and human diseases. Previous studies have generated an enormous wealth of knowledge on the events in signal-receiving cells. However, relatively little is known about the making of Wnt in signal-producing cells. Here, we describe that Gpr177, the mouse orthologue of Drosophila Wls, is expressed during formation of embryonic axes. Embryos with deficient Gpr177 exhibit defects in establishment of the body axis, a phenotype highly reminiscent to the loss of Wnt3. Although many different mammalian Wnt proteins are required for a wide range of developmental processes, the Wnt3 ablation exhibits the earliest developmental abnormality. This suggests that the Gpr177-mediated Wnt production cannot be substituted. As a direct target of Wnt, Gpr177 is activated by [beta]-catenin and LEF/TCF-dependent transcription. This activation alters the cellular distributions of Gpr177 which binds to Wnt proteins and assists their sorting and secretion in a feedback regulatory mechanism. Our findings demonstrate that the loss of Gpr177 affects Wnt production in the signal-producing cells, leading to alterations of Wnt signaling in the signal-receiving cells. A reciprocal regulation of Writ and Gpr177 is essential for the patterning of the anterior-posterior axis during mammalian development. A-P axis | [beta]-catenin | developmental deformities | primitive streak | Wnt production www.pnas.org/cgi/doi/10.1073/pnas.0900151106

Placental abnormalities occur frequently in cloned animals. Here, we attempted to isolate trophoblast stem (TS) cells from mouse blastocysts produced by somatic cell nuclear transfer (NT) at the blastocyst stage (NT blastocysts). Despite the predicted deficiency of the trophoblast cell lineage, we succeeded in isolating cell colonies with typical morphology of TS cells and cell lines from the NT blastocysts (ntTS cell lines) with efficiency as high as that from native blastocysts. The established 10 ntTS cell lines could be maintained in the undifferentiated state and induced to differentiate into several trophoblast subtypes in vitro. A comprehensive analysis of the transcriptional and epigenetic traits demonstrated that ntTS cells were indistinguishable from control TS cells. In addition, ntTS cells contributed exclusively to the placenta and survived until term in chimeras, indicating that ntTS cells have developmental potential as stem cells. Taken together, our data show that NT blastocysts contain cells that can produce TS cells in culture, suggesting that proper commitment to the trophoblast cell lineage in NT embryos occurs by the blastocyst stage. DNA methylation | epigeneticsl blastocyst | cloned animals | placenta

The nerve fiber layer of the human retina is made up of the retinal segments of ganglion cell axons. Its geometry can be described mathematically as a fibration of a 2D domain: a partition of a certain region into smooth curves. Here, we present a simple family of curves that closely models the observed geometry of the nerve fiber layer. For each retina, the pattern depends on 2 parameters, A and B: A computer program determines A and B for a given retina and the theory matches the retina with a standard deviation of [approximately or equal to] 6-8[degrees]. These particular curves turn out to be the curves that would be generated if the growing ganglion cell axon tip moved down a gradient toward a source of diffusible neuroattractant at the disk and away from a weaker macular diffusible repellant. Thus, this model provides morphological evidence that diffusible substances provide positional information to the embryonic ganglion cell axons in finding their way to the optic nerve head. diffusion | embryology | optic nerve | retina

Koeberlinia, comprising a single xerophytic species K. spinosa, had previously been placed in various families, mainly Capparaceae. Current molecular evidence now places it in its own family Koeberliniaceae, thought to be related to the Bataceae/Salvadoraceae among the 17 other families of the Brassicales. We investigated 55 embryological characters of the genus, most of which are not understood yet, and thereby assessed its systematic relationships. Koeberlinia has many embryological features in common with the Capparaceae and seven other core-Brassicalean families (i.e.. Brassicaceae, Cleomaceae, Emblingiaceae, Gyrostemonaceae, Pentadiplandraceae, Resedaceae, and Tovariaceae), specifically by possessing a campylotropous ovule with a nonmultiplicative (two-cell-layered) outer integument, reniform seeds with a curved embryo, and a fibrous exotegmen in the mature seed coat. However, Koeberlinia is clearly distinguished from them by a tenuinucellate rather than crassinucellate ovule as previously reported, markedly enlarged apical nucellar epidermal cells, and an 'exotestal' seed coat. Embryologically, Koeberlinia resembles neither the Bataceae nor the Salvadoraceae, although only limited embryological data are available for these two families. Embryological evidence thus favors its joining the core Brassicales, but additional molecular analyses and embryological studies on the missing data of the Bataceae and Salvadoraceae are needed for final confirmation of its phylogenetic position. Key words: Brassicales; embryology: Koeberlinia; Koeberliniaceae; ovule; seed.

A canonical Ras-ERK signaling pathway specifies the fate of the excretory duct cell during Caenorhabditis elegans embryogenesis. The paralogs ksr-1 and ksr-2 encode scaffolding proteins that facilitate signaling through this pathway and that act redundantly to promote the excretory duct fate. In a genomewide RNAi screen for genes that, like ksr-2, are required in combination with ksr-1 for the excretory duct cell fate, we identified 16 'ekl' (enhancer of ksr-1 lethality) genes that are largely maternally required and that have molecular identities suggesting roles in transcriptional or post-transcriptional gene regulation. These include the Argonaute gene csr-1 and a specific subset of other genes implicated in endogenous small RNA processes, orthologs of multiple components of the NuA4/Tip60 histone acetyltransferase and CCR4/NOT deadenylase complexes, and conserved enzymes involved in ubiquitination and deubiquitination. The identification of four small RNA regulators (csr-1, drh-3, ego-1, and ekl-1) that share the Ekl phenotype suggests that these genes define a functional pathway required for the production and/or function of particular germline small RNA(s). These small RNAs and the other ekl genes likely control the expression of one or more regulators of Ras-ERK signaling that function at or near the level of kinase suppressor of Ras (KSR).

Mechanisms by which the extracellular domain of Notch1 controls Notch1 signaling are not well defined. Here, we show that the O-fucose glycan in the Notch1 ligand-binding domain regulates the strength of Notch1 signaling during embryogenesis, postweaning growth, and T cell development in the mouse. Heterozygotes carrying a Notch[1.sup.12f] allele and an inactive Notch1 allele die at approximately embryonic day (E)12 with a typical Notch1 null phenotype. Homozygous Notch[1.sup.12f/12f] mice are viable and fertile but grow somewhat more slowly than littermates after weaning. Notch[1.sup.12f/12f] thymocytes bind less Delta1 and exhibit reduced Notch1 signaling. The number of double-positive (DP) and singlepositive (SP) T cells are decreased in Notch[1.sup.12f/12f] thymus, and DP T cells are more apoptotic. By contrast, proportionately more SP cells have matured, and SP-to-DP ratios are increased in mutant thymus. Thus, the O-fucose glycan in EGF12 of mouse Notch1 is required for optimal Notch1 signaling and T cell development in mammals. hypomorphic mutation | Notch signaling | O-fucosylation mutant

A study of the histology and expressions of genes involved in the neural crest in the embryology of the shallow-water-dwelling hagfish, Eptatretus burgeri is described. It is inferred that the delaminating neural crest is a vertebrate synapomorphy which is likely to have been present from the start of their evolutionary history even before separating from the hagfish family.

The ontogeny of the C-C chemokines eotaxin-1, eotaxin-2, and eotaxin-3 has not been fully elucidated in human lung. We explored a possible role for eotaxin in developing lung by determining the ontogeny of eotaxin-1 (CCL11), eotaxin-2 (CCL24), eotaxin-3 (CCL26), and the eotaxin receptor, CCR3. We tested discarded surgical samples of developing human lung tissue using quantitative RT-PCR (QRT-PCR) and immunostaining for expression of CCL11, CCL24, CCL26, and CCR3. We assessed possible functionality of the eotaxin-CCR3 system by treating lung explant cultures with exogenous CCL11 and analyzing the cultures for evidence of changes in proliferation and activation of ERK1/2, a signaling pathway associated with CCR3. QRT-PCR analyses of 22 developing lung tissue samples with gestational ages 10-23 wk demonstrated that eotaxin-1 mRNA is most abundant in developing lung, whereas mRNAs for eotaxin-2 and eotaxin-3 are minimally detectable. CCL11 mRNA levels correlated with gestational age (P < 0.05), and immunoreactivity was localized predominantly to airway epithelial cells. QRT-PCR analysis detected CCR3 expression in 16 of 19 developing lung samples. Supporting functional capacity in the immature lung, CCL11 treatment of lung explant cultures resulted in significantly increased (P < 0.05) cell proliferation and activation of the ERK signaling pathway, which is downstream from CCR3, suggesting that proliferation was due to activation of CCR3 receptors by CCL11. We conclude that developing lung expresses the eotaxins and functional CCR3 receptor. CCL11 may promote airway epithelial proliferation in the developing lung. pulmonary development; embryonic; epithelium

Despite the well-known benefits of omega-3 (n-3) polyunsaturated fatty acid (PUFA) supplementation on human health, relatively little is known about the effect of n-3 PUFA intake on fertility. More specifically, the aim of this study was to determine how oocyte and preimplantation embryo development might be influenced by n-3 PUFA supply and to understand the possible mechanisms underlying these effects. Adult female mice were fed a control diet or a diet relatively high in the long-chain n-3 PUFAs for 4 wk, and ovulated oocytes or zygotes were collected after gonadotropin stimulation. Oocytes were examined for mitochondrial parameters (active mitochondrial distribution, mitochondrial calcium and membrane potential) and oxidative stress, and embryo developmental ability was assessed at the blastocyst stage following 1) in vitro fertilization (IVF) or 2) culture of in vivo-derived zygotes. This study demonstrated that exposure of the oocyte during maturation in the ovary to an environment high in n-3 PUFA resulted in altered mitochondrial distribution and calcium levels and increased production of reactive oxygen species. Despite normal fertilization and development in vitro following IVF, the exposure of oocytes to an environment high in n-3 PUFA during in vivo fertilization adversely affected the morphological appearance of the embryo and decreased developmental ability to the blastocyst stage. This study suggests that high maternal dietary n-3 PUFA exposure periconception reduces normal embryo development in the mouse and is associated with perturbed mitochondrial metabolism, raising questions regarding supplementation with n-3 PUFAs during this period of time. oxidative stress; mitochondria

The current understanding of Xenopus laevis development provides a comparative background for the analysis of frog developmental modes. Our analysis of development in various frogs reveals that the mode of gastrulation is associated with developmental rate and is unrelated to egg size. In the gastrula of the rapidly developing embryos of the foam-nesting frogs Engystomops coloradorum and Engystomops randi, archenteron and notochord elongation overlapped with involution at the blastopore lip, as in X. laevis embryos. In embryos of dendrobatid frogs and in the frog without tadpoles Eleutherodactylus coqui, which develop somewhat more slowly than X. laevis, involution and archenteron elongation concomitantly occurred during gastrulation; whereas elongation of the notochord and, therefore, dorsal convergence and extension, occurred in the postgastrula. In contrast, in the slow developing embryos of the marsupial frog Gastrotheca riobambae, only involution occurred during gastrulation. The processes of archenteron and notochord elongation and convergence and extension were postgastrulation events. We produced an Ab against the homeodomain protein Lim1 from X. laevis as a tool for the comparative analysis of development. By the expression of Lim1, we were able to identify the dorsal side of the G. riobambae early gastrula, which otherwise was difficult to detect. Moreover, the Lim1 expression in the dorsal lip of the blastopore and notochord differed among the studied frogs, indicating variation in the timing of developmental events. The variation encountered gives evidence of the modular character of frog gastrulation. Brachyury | Gastrotheca | Lim1

Synaptic development, function and plasticity are highly regulated processes requiring a precise coordination of pre- and postsynaptic events. Recent studies have begun to highlight Wingless-Int (Wnt) signaling as a key player in synapse differentiation and function. Emerging roles of Wnts include the differentiation of synaptic specializations, microtubule dynamics, architecture of synaptic protein organization, modulation of synaptic efficacy and regulation of gene expression. These processes are driven by a variety of Wnt transduction pathways. Combined with a myriad of Wnts and Frizzled receptor family members, these pathways highlight the versatility of Wnt signaling and the potential for combinatorial use of these pathways in different aspects of synapse development and function. The identification of neurons secreting Wnt and those containing molecular components downstream of Frizzled receptors indicates that Wnts can function both as anterograde and retrograde signals. These studies open new avenues for understanding how embryonic morphogens are utilized during the development and function of synaptic networks.

Assisted reproductive technologies (ARTs) have now contributed to the birth of >3 million babies worldwide, but concerns remain regarding the safety of these methods. We have used a transgenic mouse model to examine the effects of ARTs on the frequency and spectrum of point mutations in midgestation mouse fetuses produced by either natural reproduction or various methods of ART, including preimplantation culture, embryo transfer, in vitro fertilization, intracytoplasmic sperm injection, and round spermatid injection. Our results show that there is no significant difference in the frequency or spectrum of de novo point mutations found in naturally conceived fetuses and fetuses produced by in vitro fertilization, intracytoplasmic sperm injection, or round spermatid injection. These results, based on analyses of a transgenic mouse system, indicate that with respect to maintenance of genetic integrity, ARTs appear to be safe. genetic integrity | in vitro fertilization | infertility | mutagenesis | embryology

The characteristics of the regulatory network orchestrating early mesodermal development which require the transcription factor twist as necessary factor to drive development is reported. The results suggest that twist binds to almost all mesodermal cis-regulatory modules (CRMs) to provide the competence to integrate inputs from more specialized transcription factors.

Chromatin immunoprecipitation coupled with microarray analysis (ChIP-chip) was used to determine the genome-wide occupancy of Dorsal, Twist, and Snail in the Drosophila embryo. The evidence suggests that a significant fraction of protein target enhancers is functional and extensive integration occurs between diverse patterning networks, including those controlling dorsoventral (DV) patterning and segmentation.

Contrary to the view that embryos and larvae are the most fragile stages of life, development is stable under real-world conditions. Early cleavage embryos are prepared for environmental vagaries by having high levels of cellular defenses already present in the egg before fertilization. Later in development, adaptive responses to the environment either buffer stress or produce alternative developmental phenotypes. These buffers, defenses, and alternative pathways set physiological limits for development under expected conditions; teratology occurs when embryos encounter unexpected environmental changes and when stress exceeds these limits. Of concern is that rapid anthropogenic changes to the environment are beyond the range of these protective mechanisms.

A study examines developments in the field of embryology. The gene expression of sea urchin is discussed.

Canonical and noncanonical Wnt signaling regulate crucial events in the development of vertebrates and invertebrates. In this work we show that vertebrate Diversin, a potential orthologue of Drosophila Diego, controls fusion of heart precursors and gastrulation movements in zebrafish embryogenesis, These events are regulated by noncanonical Wnt signaling, which is independent of [beta]-catenin. We found that Diversin directly interacts with Dishevelled and that this interaction is necessary and sufficient to mediate signals of the noncanonical Wnt pathway to downstream effectors like Rho family GTPases and Jun N-terminal kinase. The ankyrin repeats of Diversin are required for the interaction with Dishevelled, for the activation of noncanonical Wnt signaling, and for the biological responses. The mutation K446M in the DEP domain of vertebrate Dishevelled, which mimics a classical Drosophila loss of function mutation, prevents functional interaction with Diversin's ankyrin repeats. Diversin also affects planar cell polarity in Drosophila, which is controlled by the noncanonical Wnt signaling pathway. Our data thus demonstrate that Diversin and Dishevelled function together in a mutually dependent fashion in zebrafish gastrulation and organ formation. convergence and extension | Dishevelled | embryogenesis | noncanonical Wnt signaling | Rho family GTPases

The role of proximal and distal cis regulatory elements in gene expression of Pdx1 required for the production of duodenal gastrointestinal hormone cells and stomach gastrin cells in mice is studied.

The functioning of proteins like Noggin1 and Follistatin-like2 with Chordin to inhibit the activity of bone morphogenetic proteins in zebrafish embryos is studied.

The role of mig-5/Dsh gene in regulating cell migration and cell fate determination during embryonic and larval development of Caenorhabditis elegans is discussed.

The role of Gata6, a zinc-finger transcriptional regulator in the growth of pancreas in mouse embryos is studied.

The role of Ras signaling in the growth and proliferation of ocular lens cells in mouse embryos is studied.

The role of Notch signaling in controlling the rapid growth of midline cells in the notochord of zebra fish embryos is studied.

The contribution of Wnt signal pathway, a network of proteins in the development of hydroid patterns in the embryonic stage and metamorphosis of cnidarians is studied.

A study on the rearrangement of nuclear materials in the MHC-Oct3/4 gene locus during the development of stem cells in mouse embryos is presented.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ydbio.2006.06.032 Byline: Karen Campbell, Karl Swann Keywords: ATP; Fertilization; Ca.sup.2+ oscillations; Egg; Luciferase Abstract: Mammalian eggs and embryos rely upon mitochondrial ATP production to survive and proceed through preimplantation development. Ca.sup.2+ oscillations at fertilization have been shown to cause a reduction of mitochondrial NAD+ and flavoproteins, suggesting they might also cause changes in cytosolic ATP levels. Here, we have monitored intracellular Ca.sup.2+ and ATP levels in fertilizing mouse eggs by imaging the fluorescence of a Ca.sup.2+ dye and luminescence of firefly luciferase. At fertilization an initial increase in ATP levels occurs with the first Ca.sup.2+ transient, with a second increase occurring about 1 h later. The increase in cytosolic ATP was estimated to be from a prefertilization concentration of 1.9 mM to a peak value of 3 mM. ATP levels returned to prefertilization values as the Ca.sup.2+ oscillations terminated. An increase in ATP also occurred with other stimuli that increase Ca.sup.2+ and it was blocked when Ca.sup.2+ oscillations were inhibited by BAPTA injection. Additionally, an ATP increase was not seen when eggs were activated by cycloheximide, which does not cause a Ca.sup.2+ increase. These data suggest that mammalian fertilization is associated with a sudden but transient increase in cytosolic ATP and that Ca.sup.2+ oscillations are both necessary and sufficient to cause this increase in ATP levels. Author Affiliation: Department of Obstetrics and Gynaecology, School of Medicine, Cardiff University, Cardiff CF14 4XN, UK Article History: Received 3 April 2006; Revised 14 June 2006; Accepted 15 June 2006

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ydbio.2006.06.039 Byline: Sonia Schott, Vincent Coustham, Thomas Simonet, Cecile Bedet, Francesca Palladino Keywords: HP1; C. elegans; Gonad; Vulva Abstract: HP1 proteins are essential components of heterochromatin and contribute to the transcriptional repression of euchromatic genes. Although most species contain more than one HP1 family member which differ in their chromosomal distribution, it is not known to what extent the activity of these different family members is redundant or specific in a developmental context. C. elegans has two HP1 homologues, HPL-1 and HPL-2. While HPL-2 functions in vulval and germline development, no function has so far been attributed to HPL-1. Here we report the characterization of an hpl-1 null allele. We show that while the absence of hpl-1 alone results in no obvious phenotype, hpl-1;hpl-2 double mutants show synthetic, temperature sensitive phenotypes including larval lethality and severe defects in the development of the somatic gonad. Furthermore, we find that hpl-1 has an unexpected role in vulval development by acting redundantly with hpl-2, but not other genes previously implicated in vulval development. Localization studies show that like HPL-2, HPL-1 is a ubiquitously expressed nuclear protein. However, HPL-1 and HPL-2 localization does not completely overlap. Our results show that HPL-1 and HPL-2 play both unique and redundant functions in post-embryonic development. Author Affiliation: Laboratoire de Biologie Moleculaire de la Cellule, Ecole Normale Superieure de Lyon, CNRS UMR5161, IFR128, Lyon, France Article History: Received 21 December 2005; Revised 5 June 2006; Accepted 18 June 2006

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ydbio.2006.04.473 Byline: Sara J. Agee, Deirdre C. Lyons, David A. Weisblat Keywords: Leech; Annelid; Spiralian; nanos; D-quadrant specification; Maternal inheritants; Lophotrochozoa; Spiral cleavage; Micromeres Abstract: The gene nanos (nos) is a maternal posterior group gene required for normal development of abdominal segments and the germ line in Drosophila. Expression of nos-related genes is associated with the germ line in a broad variety of other taxa, including the leech Helobdella robusta, where zygotically expressed Hro-nos appears to be associated with primordial germ cells. The function of maternally inherited Hro-nos transcripts remains to be determined, however. Here, the function of maternal Hro-nos is examined using an antisense morpholino (MO) knockdown strategy, as confirmed by immunostaining and western blot analysis. HRO-NOS knockdown embryos exhibit abnormalities in the distribution of micromeres during cleavage. Subsequently, their germinal bands are positioned abnormally with respect to the embryonic midline and the micromere cap, epiboly fails, and the HRO-NOS knockdown embryos die. This lethality can be rescued by injection of mRNA encoding an eGFP::HRO-NOS fusion protein. HRO-NOS knockdown embryos make their normal complements of mesodermal and ectodermal teloblasts, and the progeny of these teloblasts segregate into distinct mesodermal and ectodermal layers. These results suggest that maternal Hro-nos is required for embryonic development. However, contrary to previous suggestions, maternal inherited Hro-nos does not appear necessary for ectoderm specification. Author Affiliation: Department of Molecular and Cellular Biology, 385 LSA, University of California, Berkeley, CA 94720-3200, USA Article History: Received 4 January 2006; Revised 10 April 2006; Accepted 19 April 2006

The role of mammalian receptor regulated Smad proteins, which are activated by bone morphogenetic protein signals, in the mouse embryonic development is analyzed.

The role of adhesion molecules and cell dynamics in tissue fusion and cell sorting is discussed, providing examples of their impact in embryonic development. The concept of malignant invasion, a process whereby the elimination of boundaries and compartments results in intermixing of cells, in effect, cell sorting in reverse is discussed.

The first events of the development of any embryo are under maternal control until the zygotic genome becomes activated. In the mouse embryo, the major wave of transcription activation occurs at the 2-cell stage, but transcription starts already at the zygote (1-cell) stage. Very little is known about the molecules involved in this process. We show that the transcription intermediary factor 1 [alpha] (TIF1[alpha])is involved in modulating gene expression during the first wave of transcription activation. At the onset of genome activation, TIF1[alpha] translocates from the cytoplasm into the pronuclei to sites of active transcription. These sites are enriched with the chromatin remodelers BRG-1 and SNF2H. When we ablate TIF1[alpha] through either RNA interference (RNAi) or microinjection of specific antibodies into zygotes, most of the embryos arrest their development at the 2-4-cell stage transition. The ablation of TIF1[alpha] leads to mislocalization of RNA polymerase II and the chromatin remodelers SNF2H and BRG-1. Using a chromatin immunoprecipitation cloning approach, we identify genes that are regulated by TIF1[alpha] in the zygote and find that transcription of these genes is misregulated upon TIF1[alpha] ablation. We further show that the expression of some of these genes is dependent on SNF2H and that RNAi for SNF2H compromises development, suggesting that TIF1[alpha] mediates activation of gene expression in the zygote via SNF2H. These studies indicate that TIF1[alpha] is a factor that modulates the expression of a set of genes during the first wave of genome activation in the mouse embryo.

The role of zebrafish muscle segment homeobox genes in the neural crest development and cranial placodal differentiation is examined. These genes also define the neural-nonneural border.

A study on different types of cranial placodes is presented to understand their origin, placode induction, and the role of transcription factors in placodal development. All cranial placodes are believed to originate from the panplacodal primordium.

A study on the development of embryonic lung, which is made up of several laminin isoforms, is presented. Each isoform is found to have a unique function in lung development. Laminins are important constituents of basal membrane.

The role of stage-specific embryonic antigen-1 in defining immature retinal progenitor cells controlled by Wnt signals in mouse embryos is studied.

The role of intercellular calcium ion signals in different phases of muscle development including myofibrillogenesis in vertebrate embryos is studied.

The limitation of the expression of the Nanos homolog NOS-2 gene to the germline of the embryo in Caenorhabditis elegans is studied.

The role of the Of-zen gene in the suitable occurrence of katatrepsis during development of embryo of Oncopeltus fasciatus is studied.

The role of a GTPase protein, RhoA in triggering invagination during gastrula formation in sea urchin embryos is studied.

A study on the development of the nervous system in embryos of Stichopus japonicus (sea cucumber) is presented.

The role of the foxd3 gene in the survival and migration of neural crest in embryos of zebra fishes is studied.

The asymmetrical cell division that occurs during embryonic development of Helobdella robusta (leech) is studied.

A study on the role of different pathways of RNA localization in formation of compartments in the germ plasm of zebrafish during embryonic development is presented.

The role of Rab11-family interacting protein 4 in the growth of retina in zebra fish during embryonic development is studied.

The contribution of nitric oxide in the formation of the cardiovascular systems of rodents during embryonic development is studied.