sma-9 in TGF -beta signaling pathway of Caenorhabditis elegans.
Item
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Title
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sma-9 in TGF -beta signaling pathway of Caenorhabditis elegans.
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Identifier
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AAI3187381
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identifier
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3187381
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Creator
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Liang, Jun.
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Contributor
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Adviser: Cathy Savage-Dunn
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Date
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2005
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Language
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English
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Publisher
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City University of New York.
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Subject
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Chemistry, Biochemistry | Biology, Molecular | Biology, Genetics
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Abstract
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In Caenorhabditis elegans, the DBL-1 pathway, a BMP/TGFbeta-related signaling cascade, regulates body size and male tail development. We have cloned a new gene sma-9 that encodes the C. elegans homolog of Schnurri, a large zinc finger transcription factor that regulates dpp target genes in Drosophila . Genetic interactions, sma-9 loss of function phenotype, and the expression pattern support that sma-9 acts as a downstream component and is required in the DBL-1 signaling pathway, providing the first evidence for a conserved role for Schnurri proteins in BMP signaling. Analysis of sma-9 mutant phenotypes demonstrates that SMA-9 activity is temporally and spatially restricted relative to known DBL-1 pathway components. In contrast with Drosophila schnurri, the presence of multiple alternatively spliced sma-9 transcripts suggests protein isoforms with potentially different cell sublocalization and molecular functions. We propose that SMA-9 isoforms function as transcriptional cofactors that confer specific responses to DBL-1 pathway activation.;Our genetic studies using artificial SMA-9 constructs give the first evidence that a transcriptional repressor can substitute for functional Shn protein in vivo. We showed that the sma-9 N-terminal Gln-rich region contributes to this transcriptional repressor activity by an in vitro transcriptional activity assay. Furthermore among the total genes regulated by sma-9 and dbl-1 from our microarray analysis, there are more repressed genes than activated genes. Taken together, our results suggest that SMA-9 functions as a transcriptional repressor in DBL-1 pathway regulated body size development and male tail morphogenesis.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
