The yeast mitochondrial RNA polymerase specificity factor, MTF1, is similar to bacterial sigma factors.
We have purified the protein that confers selective promoter recognition on the core subunit of the yeast mitochondrial RNA polymerase. The N-terminal sequence of the 43-kDa specificity factor identified it as the product of the MTF1 gene described by Lisowsky and Michaelis (1988). We confirmed that MTF1 encoded the specificity factor by analyzing extracts from a yeast strain bearing a disruption of the gene. The extracts contained normal levels of core RNA polymerase but lacked selective transcription activity; adding the purified 43-kDa protein restored selective transcription. Comparison of the MTF1 protein sequence to the family of bacterial sigma factors has revealed striking similarity to domains identified with--10 promoter recognition, promoter melting, and holoenzyme stability.
Department of Biology, Indiana University, Bloomington 47405.
S H
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Jang
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Jaehning
D000595:Amino Acid Sequence; D001419:Bacteria / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D005800:Genes, Fungal; D008928:Mitochondria / Q000201:enzymology / Q000378:metabolism*; D024101:Mitochondrial Proteins; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009838:Oligodeoxyribonucleotides; D011401:Promoter Regions, Genetic; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D012689:Sequence Homology, Nucleic Acid; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors; D014158:Transcription, Genetic
D005656:Fungal Proteins; C071720:MTF1 protein, S cerevisiae; D024101:Mitochondrial Proteins; D009838:Oligodeoxyribonucleotides; D029701:Saccharomyces cerevisiae Proteins; D012808:Sigma Factor; D014157:Transcription Factors; D012321:DNA-Directed RNA Polymerases