Abstract
Binding of a multiprotein complex to a 5' exon inhibitory element appears to repress splicing of the Drosophila P-element third intron (IVS3) in the soma. We have purified 97- and 50-kD proteins that interact specifically with the inhibitory element using RNA affinity chromatography. Antibodies specific for the 97-kD protein relieve inhibition of IVS3 splicing in somatic extracts, providing direct evidence that inhibition requires this protein, P-element somatic inhibitor (PSI). We identify the 50-kD protein as hrp48, a protein similar to the mammalian splicing factor hnRNP A1, and show that hrp48 recognizes specific nucleotides in a pseudo-5' splice site within the inhibitory element. The results indicate that PSI is an alternative splicing factor that regulates tissue-specific splicing, probably through interactions with generally expressed factors such as hrp48.
Publication types
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Research Support, Non-U.S. Gov't
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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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Base Sequence
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Chromatography, Affinity
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DNA Transposable Elements*
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Drosophila / genetics
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Drosophila / metabolism*
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Electrophoresis, Polyacrylamide Gel
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Exons
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Gene Expression
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Gene Expression Regulation
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HeLa Cells
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Heterogeneous Nuclear Ribonucleoprotein A1
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Heterogeneous-Nuclear Ribonucleoprotein Group A-B*
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Heterogeneous-Nuclear Ribonucleoproteins
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Humans
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Introns*
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Mammals
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Molecular Sequence Data
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Molecular Weight
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Oligodeoxyribonucleotides
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RNA Precursors / metabolism*
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RNA Splicing*
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RNA-Binding Proteins / metabolism*
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Ribonucleoproteins / genetics
Substances
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DNA Transposable Elements
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Heterogeneous Nuclear Ribonucleoprotein A1
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Heterogeneous-Nuclear Ribonucleoprotein Group A-B
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Heterogeneous-Nuclear Ribonucleoproteins
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Oligodeoxyribonucleotides
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RNA Precursors
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RNA-Binding Proteins
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Ribonucleoproteins