374 research outputs found

    Assembly of splicing complexes on exon 11 of the human insulin receptor gene does not correlate with splicing efficiency in-vitro

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    BACKGROUND: Incorporation of exon 11 of the insulin receptor gene is both developmentally and hormonally-regulated. Previously, we have shown the presence of enhancer and silencer elements that modulate the incorporation of the small 36-nucleotide exon. In this study, we investigated the role of inherent splice site strength in the alternative splicing decision and whether recognition of the splice sites is the major determinant of exon incorporation. RESULTS: We found that mutation of the flanking sub-optimal splice sites to consensus sequences caused the exon to be constitutively spliced in-vivo. These findings are consistent with the exon-definition model for splicing. In-vitro splicing of RNA templates containing exon 11 and portions of the upstream intron recapitulated the regulation seen in-vivo. Unexpectedly, we found that the splice sites are occupied and spliceosomal complex A was assembled on all templates in-vitro irrespective of splicing efficiency. CONCLUSION: These findings demonstrate that the exon-definition model explains alternative splicing of exon 11 in the IR gene in-vivo but not in-vitro. The in-vitro results suggest that the regulation occurs at a later step in spliceosome assembly on this exon

    Assessment of Short and Long-Term Changes of the Hard and Soft Tissue of the Face with Miniscrew-Assisted Rapid Maxillary Palatal Expanders

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    Maxillary transverse deficiency is a highly prevalent malocclusion present in primary and permanent dentition. In growing patients, this condition can be easily treated with a conventional rapid palatal expansion. Studies have demonstrated the possibility to expand the maxilla in non-growing patients using microimplants anchorage to correct skeletal transverse discrepancies. The purpose of this study is to evaluate the short-term and long-term changes of the hard and soft tissues of the face after microimplant-assisted expansion

    From Systematic Reviews to Clinical Recommendations for Evidence-Based Health Care: Validation of Revised Assessment of Multiple Systematic Reviews (R-AMSTAR) for Grading of Clinical Relevance

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    Research synthesis seeks to gather, examine and evaluate systematically research reports that converge toward answering a carefully crafted research question, which states the problem patient population, the intervention under consideration, and the clinical outcome of interest. The product of the process of systematically reviewing the research literature pertinent to the research question thusly stated is the “systematic review”

    A genome-wide CRISPR-Cas9 knockout screen identifies essential and growth-restricting genes in human trophoblast stem cells

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    The recent derivation of human trophoblast stem cells (hTSCs) provides a scalable in vitro model system of human placental development, but the molecular regulators of hTSC identity have not been systematically explored thus far. Here, we utilize a genome-wide CRISPR-Cas9 knockout screen to comprehensively identify essential and growth-restricting genes in hTSCs. By cross-referencing our data to those from similar genetic screens performed in other cell types, as well as gene expression data from early human embryos, we define hTSC-specific and -enriched regulators. These include both well-established and previously uncharacterized trophoblast regulators, such as ARID3A, GATA2, and TEAD1 (essential), and GCM1, PTPN14, and TET2 (growth-restricting). Integrated analysis of chromatin accessibility, gene expression, and genome-wide location data reveals that the transcription factor TEAD1 regulates the expression of many trophoblast regulators in hTSCs. In the absence of TEAD1, hTSCs fail to complete faithful differentiation into extravillous trophoblast (EVT) cells and instead show a bias towards syncytiotrophoblast (STB) differentiation, thus indicating that this transcription factor safeguards the bipotent lineage potential of hTSCs. Overall, our study provides a valuable resource for dissecting the molecular regulation of human placental development and diseases
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