Rodeheffer MS, et al. (2001) Nam1p, a protein involved in RNA processing and translation, is coupled to transcription through an interaction with yeast mitochondrial RNA polymerase. J Biol Chem 276(11):8616-22
Abstract: Alignment of three fungal mtRNA polymerases revealed conserved amino acid sequences in an amino-terminal region of the Saccharomyces cerevisiae enzyme implicated previously as harboring an important functional domain. Phenotypic analysis of deletion and point mutations, in conjunction with a yeast two-hybrid assay, revealed that Nam1p, a protein involved in RNA processing and translation in mitochondria, binds specifically to this domain. The significance of this interaction in vivo was demonstrated by the fact that the temperature-sensitive phenotype of a deletion mutation (rpo41Delta2), which impinges on this amino-terminal domain, is suppressed by overproducing Nam1p. In addition, mutations in the amino-terminal domain result specifically in decreased steady-state levels of mature mitochondrial CYTB and COXI transcripts, which is a primary defect observed in NAM1 null mutant yeast strains. Finally, one point mutation (R129D) did not abolish Nam1p binding, yet displayed an obvious COX1/CYTB transcript defect. This mutation exhibited the most severe mitochondrial phenotype, suggesting that mutations in the amino-terminal domain can perturb other critical interactions, in addition to Nam1p binding, that contribute to the observed phenotypes. These results implicate the amino-terminal domain of mtRNA polymerases in coupling additional factors and activities involved in mitochondrial gene expression directly to the transcription machinery.
|Status: Published||Type: Journal Article||PubMed ID: 11118450|
Topics addressed in this paper
Number of different genes curated to this paper: 4
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