title: Mechanism of transcription initiation by the yeast mitochondrial RNA polymerase.
abstract: Mitochondria are the major supplier of cellular energy in the form of ATP. Defects in normal ATP production due to dysfunctions in mitochondrial gene expression are responsible for many mitochondrial and aging related disorders. Mitochondria carry their own DNA genome which is transcribed by relatively simple transcriptional machinery consisting of the mitochondrial RNAP (mtRNAP) and one or more transcription factors. The mtRNAPs are remarkably similar in sequence and structure to single-subunit bacteriophage T7 RNAP but they require accessory transcription factors for promoter-specific initiation. Comparison of the mechanisms of T7 RNAP and mtRNAP provides a framework to better understand how mtRNAP and the transcription factors work together to facilitate promoter selection, DNA melting, initiating nucleotide binding, and promoter clearance. This review focuses primarily on the mechanistic characterization of transcription initiation by the yeast Saccharomyces cerevisiae mtRNAP (Rpo41) and its transcription factor (Mtf1) drawing insights from the homologous T7 and the human mitochondrial transcription systems. We discuss regulatory mechanisms of mitochondrial transcription and the idea that the mtRNAP acts as the in vivo ATP "sensor" to regulate gene expression. This article is part of a Special Issue entitled: Mitochondrial Gene Expression.
authors.affiliation: Department of Biochemistry, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, NJ 08854, USA.
authors.forename: Aishwarya P
authors.initials: AP
authors.lastname: Deshpande
authors.forename: Smita S
authors.initials: SS
authors.lastname: Patel
mesh_terms: D000255:Adenosine Triphosphate / Q000096:biosynthesis; D000595:Amino Acid Sequence; D017123:Bacteriophage T7 / Q000235:genetics / Q000378:metabolism; D004272:DNA, Mitochondrial / Q000235:genetics*; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D015394:Molecular Structure; D011401:Promoter Regions, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D004272:DNA, Mitochondrial; C071720:MTF1 protein, S cerevisiae; D024101:Mitochondrial Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D000255:Adenosine Triphosphate; D012321:DNA-Directed RNA Polymerases; C487996:RPO41 protein, S cerevisiae