Abstract
It has been generally accepted that the TATA binding protein (TBP) is a universal mediator of transcription by RNA polymerase I, II, and III. Here we report that the TBP-related factor TRF1 rather than TBP is responsible for RNA polymerase III transcription in Drosophila. Immunoprecipitation and in vitro transcription assays using immunodepleted extracts supplemented with recombinant proteins reveals that a TRF1:BRF complex is required to reconstitute transcription of tRNA, 5S and U6 RNA genes. In vivo, the majority of TRF1 is complexed with BRF and these two proteins colocalize at many polytene chromosome sites containing RNA pol III genes. These data suggest that in Drosophila, TRF1 rather than TBP forms a complex with BRF that plays a major role in RNA pol III transcription.
MeSH terms
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Amino Acid Sequence
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Animals
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Base Sequence
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Cloning, Molecular
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DNA, Complementary
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism*
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Drosophila / enzymology
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Drosophila / genetics
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Drosophila Proteins*
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Humans
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Insect Proteins / genetics
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Insect Proteins / metabolism*
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Mice
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Molecular Sequence Data
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RNA Polymerase III / 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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Saccharomyces cerevisiae Proteins
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Sequence Homology, Amino Acid
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TATA Box Binding Protein-Like Proteins
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TATA-Binding Protein Associated Factors
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TATA-Box Binding Protein
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Transcription Factor TFIIIB*
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Transcription Factors / genetics
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Transcription Factors / metabolism*
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Transcription, Genetic*
Substances
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BRF1 protein, S cerevisiae
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BRF1 protein, human
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DNA, Complementary
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DNA-Binding Proteins
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Drosophila Proteins
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Insect Proteins
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Recombinant Fusion Proteins
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Saccharomyces cerevisiae Proteins
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TATA Box Binding Protein-Like Proteins
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TATA-Binding Protein Associated Factors
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TATA-Box Binding Protein
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TBP-related factor, Drosophila
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Transcription Factor TFIIIB
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Transcription Factors
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RNA Polymerase III