title: Characterization of Gtf1p, the connector subunit of yeast mitochondrial tRNA-dependent amidotransferase.
abstract: The bacterial GatCAB operon for tRNA-dependent amidotransferase (AdT) catalyzes the transamidation of mischarged glutamyl-tRNA(Gln) to glutaminyl-tRNA(Gln). Here we describe the phenotype of temperature-sensitive (ts) mutants of GTF1, a gene proposed to code for subunit F of mitochondrial AdT in Saccharomyces cerevisiae. The ts gtf1 mutants accumulate an electrophoretic variant of the mitochondrially encoded Cox2p subunit of cytochrome oxidase and an unstable form of the Atp8p subunit of the F(1)-F(0) ATP synthase that is degraded, thereby preventing assembly of the F(0) sector. Allotopic expression of recoded ATP8 and COX2 did not significantly improve growth of gtf1 mutants on respiratory substrates. However, ts gft1 mutants are partially rescued by overexpression of PET112 and HER2 that code for the yeast homologues of the catalytic subunits of bacterial AdT. Additionally, B66, a her2 point mutant has a phenotype similar to that of gtf1 mutants. These results provide genetic support for the essentiality, in vivo, of the GatF subunit of the heterotrimeric AdT that catalyzes formation of glutaminyl-tRNA(Gln) (Frechin, M., Senger, B., Brayé, M., Kern, D., Martin, R. P., and Becker, H. D. (2009) Genes Dev. 23, 1119-1130).
authors.affiliation: Department of Microbiology, University of São Paulo, 05508-900 São Paulo, Brazil.
authors.forename: Mario H
authors.initials: MH
authors.lastname: Barros
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Rak
authors.forename: Janaina A
authors.initials: JA
authors.lastname: Paulela
authors.forename: Alexander
authors.initials: A
authors.lastname: Tzagoloff
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000595:Amino Acid Sequence; D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D000968:Antimycin A / Q000031:analogs & derivatives / Q000494:pharmacology; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D050259:Genes, Mitochondrial / Q000235:genetics; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D009154:Mutation / Q000235:genetics; D009245:NADH Dehydrogenase / Q000378:metabolism; D019884:Nitrogenous Group Transferases / Q000378:metabolism*; D010455:Peptides / Q000737:chemistry; D010641:Phenotype; D014176:Protein Biosynthesis / Q000187:drug effects; D021122:Protein Subunits / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012343:RNA, Transfer / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D013696:Temperature
chemical_list: D010455:Peptides; D021122:Protein Subunits; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; C032456:antimycin; D000968:Antimycin A; D012343:RNA, Transfer; D009245:NADH Dehydrogenase; C000589643:Her2 protein, S cerevisiae; D019884:Nitrogenous Group Transferases; D000251:Adenosine Triphosphatases; D000604:Amino Acyl-tRNA Synthetases; C567965:glutaminyl transamidase subunit F, S cerevisiae