Multiple functions of yeast mitochondrial transcription factor Mtf1p during initiation.
Transcription of the yeast mitochondrial genome is carried out by an RNA polymerase (Rpo41p) that is related to single subunit bacteriophage RNA polymerases but requires an additional factor (Mtf1p) for initiation. In this work we show that Mtf1p is involved in multiple roles during initiation including discrimination of upstream base pairs in the promoter, initial melting of three to four base pairs around the site of transcript initiation, and suppression of nonspecific initiation. It, thus, appears that Mtf1p is functionally analogous to initiation factors of multisubunit RNA polymerases, such as sigma. Photocross-linking experiments reveal close proximity between Mtf1p and the promoter DNA and show that the C-terminal domain makes contacts with the template strand in the vicinity of the start site. Interestingly, Mtf1p is related to a class of RNA methyltransferases, suggesting an early evolutionary link between RNA synthesis and processing.
Savkina
Maria
M
From the Department of Cell Biology, School of Osteopathic Medicine, University of Medicine and Dentistry of New Jersey, Stratford Division, Stratford, New Jersey 08084; Graduate School of Biomedical Sciences, University of Medicine and Dentistry of New Jersey, Stratford Division, Stratford, New Jersey 08084.
Temiakov
Dmitry
D
From the Department of Cell Biology, School of Osteopathic Medicine, University of Medicine and Dentistry of New Jersey, Stratford Division, Stratford, New Jersey 08084.
McAllister
William T
WT
From the Department of Cell Biology, School of Osteopathic Medicine, University of Medicine and Dentistry of New Jersey, Stratford Division, Stratford, New Jersey 08084.
Anikin
Michael
M
From the Department of Cell Biology, School of Osteopathic Medicine, University of Medicine and Dentistry of New Jersey, Stratford Division, Stratford, New Jersey 08084. Electronic address: anikinmi@umdnj.edu.
D001483:Base Sequence; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004272:DNA, Mitochondrial / Q000235:genetics*; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008954:Models, Biological; D009154:Mutation; D009690:Nucleic Acid Conformation; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D024363:Transcription Initiation Site; D014158:Transcription, Genetic
D004271:DNA, Fungal; D004272:DNA, Mitochondrial; C071720:MTF1 protein, S cerevisiae; D024101:Mitochondrial Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D012321:DNA-Directed RNA Polymerases; C487996:RPO41 protein, S cerevisiae