Abstract
A cap-binding protein complex (CBC) present in the nuclei of HeLa cells has been characterized. Purified CBC consists of two previously identified proteins, CBP80 and CBP20. These proteins are shown to cofractionate to apparent homogeneity and to be coimmunoprecipitable with anti-CBP80 antibodies. Analysis of the inhibition of pre-mRNA splicing in vitro and in vivo by chemically modified analogs of the cap structure, and of the binding of these analogs to CBC in vitro, suggests a role for the complex in splicing. Extracts immunodepleted of CBC do not efficiently splice an adenoviral pre-mRNA owing to blockage of an early step in splicing complex formation. CBC may therefore play a role in pre-mRNA recognition.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Antibody Specificity
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Cell Extracts
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Cell Nucleus / metabolism
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Cloning, Molecular
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HeLa Cells
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Humans
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Molecular Sequence Data
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Protein Binding
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RNA Cap Analogs
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RNA Cap-Binding Proteins
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RNA Caps / metabolism*
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RNA Precursors / metabolism*
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RNA Splicing / physiology*
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RNA-Binding Proteins / genetics
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RNA-Binding Proteins / isolation & purification
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RNA-Binding Proteins / metabolism*
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Recombinant Fusion Proteins / analysis
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Recombinant Fusion Proteins / immunology
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Sequence Analysis, DNA
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Spliceosomes / metabolism
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Xenopus laevis
Substances
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Cell Extracts
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RNA Cap Analogs
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RNA Cap-Binding Proteins
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RNA Caps
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RNA Precursors
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RNA-Binding Proteins
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Recombinant Fusion Proteins