14 results on '"Cheung LE"'
Search Results
2. Noncardiac DiGeorge syndrome diagnosed with multiplex ligation-dependent probe amplification: A case report
- Author
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Chih-Hsuan Fu, Cheung Leung, Chuan-Hong Kao, and Shu-Jen Yeh
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deletion 22q11 ,DiGeorge syndrome ,multiplex ligation-dependent probe amplification ,Medicine (General) ,R5-920 - Abstract
DiGeorge syndrome is not really a rare disease. A microdeletion of chromosome 22q11.2 is found in most patients. Sharing the same genetic cause, a wide spectrum of clinical manifestations such as conotruncal anomaly face syndrome, Cayler cardiofacial syndrome, and velocardiofacial syndrome have been reported. Classic characteristics are cardiac defects, abnormal facial features, thymic hypoplasia, cleft palate, and hypocalcemia. We report a 6-year-old female child presenting with generalized seizure resulting from hypocalcemia. She had no cardiac defects and no hypocalcemia episode in neonatal stage, and had been said to be normal before by her parents until the diagnosis was made. This highlights the importance of extracardiac manifestations in the diagnosis of DiGeorge syndrome, and many affected patients may be underestimated with minor facial dysmorphism. As health practitioners, it is our duty to identify the victims undermined in the population, and start thorough investigations and the following rehabilitation as soon as possible. Multiplex ligation-dependent probe amplification is a rapid, reliable, and economical alternative for the diagnosis of 22q11.2 deletion.
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- 2015
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3. Parental Smoking During Pregnancy and Its Association with Low Birth Weight, Small for Gestational Age, and Preterm Birth Offspring: A Birth Cohort Study
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Ting-Jung Ko, Li-Yi Tsai, Li-Ching Chu, Shu-Jen Yeh, Cheung Leung, Chien-Yi Chen, Hung-Chieh Chou, Po-Nien Tsao, Pau-Chung Chen, and Wu-Shiun Hsieh
- Subjects
low birth weight ,preterm ,smoking ,birth cohort ,Pediatrics ,RJ1-570 - Abstract
Intrauterine exposure to tobacco smoke has been discerned as an important risk factor for low birth weight (LBW), small for gestational age (SGA), and preterm birth infants. In this cohort study, we investigated the association of the amount of parental smoking during the different pregnancy stages with birth weight and the incidence of preterm delivery. Methods: Our study population was acquired from the Taiwan Birth Cohort Study. Between June 2005 and July 2006, 21,248 postpartum women were interviewed 6 months after their deliveries by a structured questionnaire. The parents were divided into four groups according to the amount of smoking during preconception, the first trimester, and the second and third trimesters. The relationships of parental smoking with gestational age and birth weight during the different pregnancy stages were assessed using multivariate linear regression. Multiple logistic regression analyses were performed to estimate the odds ratios and 95% confidence intervals of preterm delivery, LBW, and SGA infants during the different parental smoking status and the different pregnancy stages. Results: After adjusting for the physical and socioeconomic status of the parents and for paternal smoking during the same period, we found that maternal smoking decreased birth weight. Compared with the nonsmoking groups, all the maternal smoking groups had higher incidences of LBW, SGA, and preterm birth infants, especially when the mothers smoked >20 cigarettes/day. The association of paternal smoking with LBW, SGA, and preterm birth infants was insignificant. Conclusion: Maternal smoking is responsible for increased incidences of LBW and preterm delivery of babies, and therefore, smoking cessation/reduction should be advised to pregnant women to reduce morbidities in their neonates. Further studies are needed to clarify the correlation of fetal health with passive smoking, including exposure to environmental tobacco smoke and to other smokers in the family.
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- 2014
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4. Hypernatremic Dehydration Due to Concentrated Infant Formula: Report of Two Cases
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Cheung Leung, Wen-Cheng Chang, and Shu-Jen Yeh
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dehydration ,hypernatremia ,newborn ,Pediatrics ,RJ1-570 - Abstract
Hypernatremic dehydration is a rare but serious clinical condition in newborns and small infants. It is usually caused by diarrhea, improperly prepared infant formula, decreased fluid intake, or exclusive breastfeeding. Symptoms are usually masked until neurological symptoms occur. We report two infants who presented with fever and hypernatremic dehydration caused by concentrating infant formula to alleviate symptoms of constipation, and careless formula preparation due to confusion over spoon sizes, respectively. In the first case, status epilepticus occurred during early treatment, despite close serum sodium monitoring, though the infant was asymptomatic and thriving 4 years after discharge, with no identified neurodevelopmental deficits. The course of treatment was smooth in the second case, and no neurological complications developed. The practice of concentrating infant formula to relieve symptoms of constipation, although temporarily effective, is hazardous to newborns or young infants and can cause hypernatremic dehydration. Spoon sizes supplied with commercial infant formulas (30 mL/spoonful or 60 mL/spoonful) should be unified to avoid mistakes during preparation, especially by inexperienced and teenage mothers.
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- 2009
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5. Video-assisted Thoracoscopic Surgery in a 1-month-old Infant with Pleural Empyema
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Cheung Leung
- Subjects
empyema ,pediatric ,video-assisted thoracoscopic surgery ,Medicine (General) ,R5-920 - Abstract
Pleural empyema is a frequent complication of bacterial pneumonia in childhood but is rare in neonates. Various modalities of treatment from intravenous antibiotics, chest tube drainage, intrapleural fibrinolytic agent installation, video-assisted thoracostomy to surgical decortication have been suggested to treat different stages of empyema in children, but management of progressive empyema in neonates is still at the stage of antimicrobial therapy and tube thoracostomy. Here, we report a 1-month-old infant with staphy-lococcal pneumonia complicated with multiloculated empyema who was successfully treated with video-assisted thoracoscopic surgery (VATS) after 4 days of chest tube drainage and parenteral antibiotics. The patient's condition improved rapidly after the operation and the antimicrobial therapy was continued for 3 weeks. He was asymptomatic and thriving at follow-up 1 year later. Chest radiography at 1 month was free of any lesion. This case suggests that VATS can be a safe and effective treatment for neonatal empyema.
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- 2006
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6. An Infant With Transient Neonatal Pustular Melanosis Presenting as Pustules
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Pei-San Chia, Cheung Leung, Yu-Ling Hsu, and Cheng-Yu Lo
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pustules ,newborn ,transient neonatal pustular melanosis ,Pediatrics ,RJ1-570 - Abstract
Transient neonatal pustular melanosis is mostly found in full-term black infants. It is a benign and self-limited disease, and the etiology is still unknown. We present a full-term female neonate with multiple vesiculopustular and pigmented macular lesions found immediately after her birth. A skin biopsy showed vesicles consisting of intracorneal and subcorneal aggregates of neutrophils, which is compatible with transient neonatal pustular melanosis. Although it is rare in Taiwan and Asian countries, transient neonatal pustular melanosis should always be considered when pustulosis is found in the neonatal period to prevent the use of unnecessary antibiotics. Dermatological consultation and histological confirmation are sometimes required for the final diagnosis.
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- 2010
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7. Kernel-imbedded Gaussian processes for disease classification using microarray gene expression data
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Cheung Leo and Zhao Xin
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Computer applications to medicine. Medical informatics ,R858-859.7 ,Biology (General) ,QH301-705.5 - Abstract
Abstract Background Designing appropriate machine learning methods for identifying genes that have a significant discriminating power for disease outcomes has become more and more important for our understanding of diseases at genomic level. Although many machine learning methods have been developed and applied to the area of microarray gene expression data analysis, the majority of them are based on linear models, which however are not necessarily appropriate for the underlying connection between the target disease and its associated explanatory genes. Linear model based methods usually also bring in false positive significant features more easily. Furthermore, linear model based algorithms often involve calculating the inverse of a matrix that is possibly singular when the number of potentially important genes is relatively large. This leads to problems of numerical instability. To overcome these limitations, a few non-linear methods have recently been introduced to the area. Many of the existing non-linear methods have a couple of critical problems, the model selection problem and the model parameter tuning problem, that remain unsolved or even untouched. In general, a unified framework that allows model parameters of both linear and non-linear models to be easily tuned is always preferred in real-world applications. Kernel-induced learning methods form a class of approaches that show promising potentials to achieve this goal. Results A hierarchical statistical model named kernel-imbedded Gaussian process (KIGP) is developed under a unified Bayesian framework for binary disease classification problems using microarray gene expression data. In particular, based on a probit regression setting, an adaptive algorithm with a cascading structure is designed to find the appropriate kernel, to discover the potentially significant genes, and to make the optimal class prediction accordingly. A Gibbs sampler is built as the core of the algorithm to make Bayesian inferences. Simulation studies showed that, even without any knowledge of the underlying generative model, the KIGP performed very close to the theoretical Bayesian bound not only in the case with a linear Bayesian classifier but also in the case with a very non-linear Bayesian classifier. This sheds light on its broader usability to microarray data analysis problems, especially to those that linear methods work awkwardly. The KIGP was also applied to four published microarray datasets, and the results showed that the KIGP performed better than or at least as well as any of the referred state-of-the-art methods did in all of these cases. Conclusion Mathematically built on the kernel-induced feature space concept under a Bayesian framework, the KIGP method presented in this paper provides a unified machine learning approach to explore both the linear and the possibly non-linear underlying relationship between the target features of a given binary disease classification problem and the related explanatory gene expression data. More importantly, it incorporates the model parameter tuning into the framework. The model selection problem is addressed in the form of selecting a proper kernel type. The KIGP method also gives Bayesian probabilistic predictions for disease classification. These properties and features are beneficial to most real-world applications. The algorithm is naturally robust in numerical computation. The simulation studies and the published data studies demonstrated that the proposed KIGP performs satisfactorily and consistently.
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- 2007
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8. The Broad-Spectrum Antiviral Protein ZAP Restricts Human Retrotransposition.
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Goodier JL, Pereira GC, Cheung LE, Rose RJ, and Kazazian HH Jr
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- Cloning, Molecular, DNA Viruses genetics, Evolution, Molecular, Green Fluorescent Proteins genetics, Green Fluorescent Proteins metabolism, HEK293 Cells, HeLa Cells, Humans, Immunoprecipitation, Interferon Regulatory Factors genetics, Interferon Regulatory Factors metabolism, RNA Helicases genetics, RNA Helicases metabolism, RNA Stability, RNA-Binding Proteins genetics, RNA-Binding Proteins metabolism, Retroelements
- Abstract
Intrinsic immunity describes the set of recently discovered but poorly understood cellular mechanisms that specifically target viral pathogens. Their discovery derives in large part from intensive studies of HIV and SIV that revealed restriction factors acting at various stages of the retroviral life cycle. Recent studies indicate that some factors restrict both retroviruses and retrotransposons but surprisingly in ways that may differ. We screened known interferon-stimulated antiviral proteins previously untested for their effects on cell culture retrotransposition. Several factors, including BST2, ISG20, MAVS, MX2, and ZAP, showed strong L1 inhibition. We focused on ZAP (PARP13/ZC3HAV1), a zinc-finger protein that targets viruses of several families, including Retroviridae, Tiloviridae, and Togaviridae, and show that ZAP expression also strongly restricts retrotransposition in cell culture through loss of L1 RNA and ribonucleoprotein particle integrity. Association of ZAP with the L1 ribonucleoprotein particle is supported by co-immunoprecipitation and co-localization with ORF1p in cytoplasmic stress granules. We also used mass spectrometry to determine the protein components of the ZAP interactome, and identified many proteins that directly interact and colocalize with ZAP, including MOV10, an RNA helicase previously shown to suppress retrotransposons. The detection of a chaperonin complex, RNA degradation proteins, helicases, post-translational modifiers, and components of chromatin modifying complexes suggest mechanisms of ZAP anti-retroelement activity that function in the cytoplasm and perhaps also in the nucleus. The association of the ZAP ribonucleoprotein particle with many interferon-stimulated gene products indicates it may be a key player in the interferon response.
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- 2015
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9. Modulation of LINE-1 and Alu/SVA retrotransposition by Aicardi-Goutières syndrome-related SAMHD1.
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Zhao K, Du J, Han X, Goodier JL, Li P, Zhou X, Wei W, Evans SL, Li L, Zhang W, Cheung LE, Wang G, Kazazian HH Jr, and Yu XF
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- Alu Elements, HEK293 Cells, HeLa Cells, Humans, Open Reading Frames, Ribonucleoproteins genetics, SAM Domain and HD Domain-Containing Protein 1, Sequence Alignment, Transfection, Autoimmune Diseases of the Nervous System genetics, Long Interspersed Nucleotide Elements, Monomeric GTP-Binding Proteins genetics, Nervous System Malformations genetics
- Abstract
Long interspersed elements 1 (LINE-1) occupy at least 17% of the human genome and are its only active autonomous retrotransposons. However, the host factors that regulate LINE-1 retrotransposition are not fully understood. Here, we demonstrate that the Aicardi-Goutières syndrome gene product SAMHD1, recently revealed to be an inhibitor of HIV/simian immunodeficiency virus (SIV) infectivity and neutralized by the viral Vpx protein, is also a potent regulator of LINE-1 and LINE-1-mediated Alu/SVA retrotransposition. We also found that mutant SAMHD1s of Aicardi-Goutières syndrome patients are defective in LINE-1 inhibition. Several domains of SAMHD1 are critical for LINE-1 regulation. SAMHD1 inhibits LINE-1 retrotransposition in dividing cells. An enzymatic active site mutant SAMHD1 maintained substantial anti-LINE-1 activity. SAMHD1 inhibits ORF2p-mediated LINE-1 reverse transcription in isolated LINE-1 ribonucleoproteins by reducing ORF2p level. Thus, SAMHD1 may be a cellular regulator of LINE-1 activity that is conserved in mammals., (Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2013
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10. In vitro screening for compounds that enhance human L1 mobilization.
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Terasaki N, Goodier JL, Cheung LE, Wang YJ, Kajikawa M, Kazazian HH Jr, and Okada N
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- Anti-Inflammatory Agents, Non-Steroidal chemistry, Genes, Reporter, HEK293 Cells, HeLa Cells, Hep G2 Cells, Humans, Mutagens chemistry, Oxidative Stress, PPAR alpha agonists, Promoter Regions, Genetic, Transcription, Genetic, Drug Evaluation, Preclinical, Long Interspersed Nucleotide Elements genetics, Salicylamides chemistry
- Abstract
The Long interspersed element 1 (LINE1 or L1) retrotransposon constitutes 17% of the human genome. There are currently 80-100 human L1 elements that are thought to be active in any diploid human genome. These elements can mobilize into new locations of the genome, resulting in changes in genomic information. Active L1s are thus considered to be a type of endogenous mutagen, and L1 insertions can cause disease. Certain stresses, such as gamma radiation, oxidative stress, and treatment with some agents, can induce transcription and/or mobilization of retrotransposons. In this study, we used a reporter gene assay in HepG2 cells to screen compounds for the potential to enhance the transcription of human L1. We assessed 95 compounds including genotoxic agents, substances that induce cellular stress, and commercially available drugs. Treatment with 15 compounds increased the L1 promoter activity by >1.5-fold (p<0.05) after 6 or 24 hours of treatment. In particular, genotoxic agents (benzo[a]pyrene, camptothecin, cytochalasin D, merbarone, and vinblastine), PPARα agonists (bezafibrate and fenofibrate), and non-steroidal anti-inflammatory drugs (diflunisal, flufenamic acid, salicylamide, and sulindac) induced L1 promoter activity. To examine their effects on L1 retrotransposition, we developed a high-throughput real-time retrotransposition assay using a novel secreted Gaussia luciferase reporter cassette. Three compounds (etomoxir, WY-14643, and salicylamide) produced a significant enhancement in L1 retrotransposition. This is the first study to report the effects of a wide variety of compounds on L1 transcription and retrotransposition. These results suggest that certain chemical- and drug-induced stresses might have the potential to cause genomic mutations by inducing L1 mobilization. Thus, the risk of induced L1 transcription and retrotransposition should be considered during drug safety evaluation and environmental risk assessments of chemicals.
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- 2013
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11. Mapping the LINE1 ORF1 protein interactome reveals associated inhibitors of human retrotransposition.
- Author
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Goodier JL, Cheung LE, and Kazazian HH Jr
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- Cell Survival, Cytoplasmic Granules metabolism, Green Fluorescent Proteins genetics, Green Fluorescent Proteins metabolism, HEK293 Cells, HIV-1, HeLa Cells, Humans, Multiprotein Complexes genetics, Multiprotein Complexes metabolism, Proteins genetics, Pseudogenes, RNA Helicases genetics, RNA Helicases metabolism, RNA Transport, Ribonucleoproteins genetics, Ribonucleoproteins metabolism, Transcription, Genetic, Protein Interaction Mapping methods, Proteins metabolism, Retroelements
- Abstract
LINE1s occupy 17% of the human genome and are its only active autonomous mobile DNA. L1s are also responsible for genomic insertion of processed pseudogenes and >1 million non-autonomous retrotransposons (Alus and SVAs). These elements have significant effects on gene organization and expression. Despite the importance of retrotransposons for genome evolution, much about their biology remains unknown, including cellular factors involved in the complex processes of retrotransposition and forming and transporting L1 ribonucleoprotein particles. By co-immunoprecipitation of tagged L1 constructs and mass spectrometry, we identified proteins associated with the L1 ORF1 protein and its ribonucleoprotein. These include RNA transport proteins, gene expression regulators, post-translational modifiers, helicases and splicing factors. Many cellular proteins co-localize with L1 ORF1 protein in cytoplasmic granules. We also assayed the effects of these proteins on cell culture retrotransposition and found strong inhibiting proteins, including some that control HIV and other retroviruses. These data suggest candidate cofactors that interact with the L1 to modulate its activity and increase our understanding of the means by which the cell coexists with these genomic 'parasites'.
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- 2013
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12. The minimal active human SVA retrotransposon requires only the 5'-hexamer and Alu-like domains.
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Hancks DC, Mandal PK, Cheung LE, and Kazazian HH Jr
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- Cell Line, Tumor, Genes, Reporter, Green Fluorescent Proteins, Humans, Minisatellite Repeats, Mutagenesis, Insertional, RNA, Untranslated chemistry, RNA, Untranslated metabolism, RNA-Directed DNA Polymerase genetics, RNA-Directed DNA Polymerase metabolism, Alu Elements, Long Interspersed Nucleotide Elements, RNA, Untranslated genetics, Reverse Transcription
- Abstract
RNA-based duplication mediated by reverse transcriptase (RT), a process termed retrotransposition, is ongoing in humans and is a source of significant inter- and perhaps intraindividual genomic variation. The long interspersed element 1 (LINE-1 or L1) ORF2 protein is the genomic source for RT activity required for mobilization of its own RNA in cis and other RNAs, such as SINE/variable-number tandem-repeat (VNTR)/Alu (SVA) elements, in trans. SVA elements are ~2-kb hominid-specific noncoding RNAs that have resulted in single-gene disease in humans through insertional mutagenesis or aberrant mRNA splicing. Here, using an SVA retrotransposition cell culture assay in U2OS cells, we investigated SVA domains important in L1-mediated SVA retrotransposition. Partial- and whole-domain deletions revealed that removal of either the Alu-like or SINE-R domain in the context of a full-length SVA has little to no effect, whereas removal of the CT hexamer or the VNTR domain can result in a 75% decrease in activity. Additional experiments demonstrate that the Alu-like fragment alone can retrotranspose at low levels while the addition of the CT hexamer can enhance activity as much as 2-fold compared to that of the full-length SVA. These results suggest that no SVA domain is essential for retrotransposition in U2OS cells and that the 5' end of SVA (hexamer and Alu-like domain) is sufficient for retrotransposition.
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- 2012
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13. MOV10 RNA helicase is a potent inhibitor of retrotransposition in cells.
- Author
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Goodier JL, Cheung LE, and Kazazian HH Jr
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- Adenosine Triphosphate metabolism, Amino Acid Motifs, Animals, Cell Line, Cytoplasmic Granules metabolism, Gene Expression, Humans, Mutagenesis, Insertional, Protein Binding, Protein Transport, RNA Helicases chemistry, Ribonucleoproteins genetics, Ribonucleoproteins metabolism, RNA Helicases metabolism, Retroelements
- Abstract
MOV10 protein, a putative RNA helicase and component of the RNA-induced silencing complex (RISC), inhibits retrovirus replication. We show that MOV10 also severely restricts human LINE1 (L1), Alu, and SVA retrotransposons. MOV10 associates with the L1 ribonucleoprotein particle, along with other RNA helicases including DDX5, DHX9, DDX17, DDX21, and DDX39A. However, unlike MOV10, these other helicases do not strongly inhibit retrotransposition, an activity dependent upon intact helicase domains. MOV10 association with retrotransposons is further supported by its colocalization with L1 ORF1 protein in stress granules, by cytoplasmic structures associated with RNA silencing, and by the ability of MOV10 to reduce endogenous and ectopic L1 expression. The majority of the human genome is repetitive DNA, most of which is the detritus of millions of years of accumulated retrotransposition. Retrotransposons remain active mutagens, and their insertion can disrupt gene function. Therefore, the host has evolved defense mechanisms to protect against retrotransposition, an arsenal we are only beginning to understand. With homologs in other vertebrates, insects, and plants, MOV10 may represent an ancient and innate form of immunity against both infective viruses and endogenous retroelements., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2012
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14. Retrotransposition of marked SVA elements by human L1s in cultured cells.
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Hancks DC, Goodier JL, Mandal PK, Cheung LE, and Kazazian HH Jr
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- Alu Elements genetics, Blotting, Northern, Cell Line, Cell Line, Tumor, HeLa Cells, Humans, Minisatellite Repeats genetics, Polymerase Chain Reaction, Short Interspersed Nucleotide Elements genetics, Transcription Initiation Site, Retroelements genetics
- Abstract
Human retrotransposons generate structural variation and genomic diversity through ongoing retrotransposition and non-allelic homologous recombination. Cell culture retrotransposition assays have provided great insight into the genomic impact of retrotransposons, in particular, LINE-1(L1) and Alu elements; however, no such assay exists for the youngest active human retrotransposon, SINE-VNTR-Alu (SVA). Here we report the development of an SVA cell culture retrotransposition assay. We marked several SVAs with either neomycin or EGFP retrotransposition indicator cassettes. Engineered SVAs retrotranspose using L1 proteins supplemented in trans in multiple cell lines, including U2OS osteosarcoma cells where SVA retrotransposition is equal to that of an engineered L1. Engineered SVAs retrotranspose at 1-54 times the frequency of a marked pseudogene in HeLa HA cells. Furthermore, our data suggest a variable requirement for L1 ORF1p for SVA retrotransposition. Recovered engineered SVA insertions display all the hallmarks of LINE-1 retrotransposition and some contain 5' and 3' transductions, which are common for genomic SVAs. Of particular interest is the fact that four out of five insertions recovered from one SVA are full-length, with the 5' end of these insertions beginning within 5 nt of the CMV promoter transcriptional start site. This assay demonstrates that SVA elements are indeed mobilized in trans by L1. Previously intractable questions regarding SVA biology can now be addressed.
- Published
- 2011
- Full Text
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