title: Origins of transcripts of the yeast mitochondrial var 1 gene.
abstract: Transcription of the yeast mitochondrial var 1 gene encoding the mitochondrial small ribosomal subunit protein, var 1, has been examined in wild type and petite strains by Northern hybridization, S 1 nuclease protection experiments, and analysis of primary transcripts by in vitro labeling of mitochondrial RNAs with [alpha-32P]GTP and guanylyl transferase. We have identified a transcription unit in which a polycistronic precursor gives rise to the mRNAs for ATPase subunit 9 (the product of the oli 1 gene), var 1, and tRNASerUCN. Potential cleavage sites have been identified within this precursor that separates oli 1, tRNASerUCN, and var 1 transcripts. Transcriptional initiation of the polycistronic precursor occurs from one of two nearby copies of the sequence, 5'-ATATAAGTA-3', located approximately 550 and 630 base pairs 5' to the oli 1 gene. A closely related sequence, 5'-TTATAAGTA-3', is found within the var 1 gene and may serve as a transcriptional initiation site for one of a pair of primary transcripts detected in a petite retaining the var 1[40.0] allele. The other primary transcript in this strain initiates upstream in a region of the var 1 gene containing no recognizable initiation sites.
mesh_terms: D001483:Base Sequence; D004262:DNA Restriction Enzymes; D004272:DNA, Mitochondrial / Q000235:genetics*; D005656:Fungal Proteins / Q000235:genetics*; D005796:Genes; D005800:Genes, Fungal; D008565:Membrane Proteins; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins; D009693:Nucleic Acid Hybridization; D012269:Ribosomal Proteins / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D014158:Transcription, Genetic
chemical_list: D004272:DNA, Mitochondrial; D005656:Fungal Proteins; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D012269:Ribosomal Proteins; D029701:Saccharomyces cerevisiae Proteins; C026383:VAR1 protein, S cerevisiae; D004262:DNA Restriction Enzymes