Abstract
SR proteins constitute a family of pre-mRNA splicing factors that play important roles in both constitutive and regulated splicing. Here, we describe one member of the family, which we call SRp38, with unexpected properties. Unlike other SR proteins, SRp38 cannot activate splicing and is essentially inactive in splicing assays. However, dephosphorylation converts SRp38 to a potent, general repressor that inhibits splicing at an early step. To investigate the cellular function of SRp38, we examined its possible role in cell cycle control. We show first that splicing, like other steps in gene expression, is inhibited in extracts of mitotic cells. Strikingly, SRp38 was found to be dephosphorylated specifically in mitotic cells, and we show that dephosphorylated SRp38 is required for the observed splicing repression.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Alternative Splicing*
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Animals
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Carrier Proteins / genetics
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Carrier Proteins / metabolism*
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism*
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Cell Extracts
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Female
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HeLa Cells
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Humans
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Male
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Mice
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Mitosis / physiology
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Neoplasm Proteins / genetics
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Neoplasm Proteins / metabolism*
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Phosphorylation
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RNA Precursors*
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RNA-Binding Proteins / genetics
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RNA-Binding Proteins / metabolism*
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Rabbits
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Repressor Proteins / genetics
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Repressor Proteins / metabolism*
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Serine-Arginine Splicing Factors
Substances
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Carrier Proteins
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Cell Cycle Proteins
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Cell Extracts
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Fusip1 protein, mouse
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Neoplasm Proteins
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RNA Precursors
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RNA-Binding Proteins
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Recombinant Fusion Proteins
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Repressor Proteins
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SRSF10 protein, human
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Serine-Arginine Splicing Factors