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Query: EC:3.6.3.14 (ATP synthase)
 7,042 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The yeast mitochondrial genome encodes only seven major components of the respiratory chain and ATP synthase; more than 200 other mitochondrial proteins are encoded by nuclear genes. Thus, assembly of functional mitochondria requires coordinate expression of nuclear and mitochondrial genes. One example of coordinate regulation is the stabilization of mitochondrial COB (cytochrome b) mRNA by Cbp1, the product of the nuclear gene CBP1 (cytochrome b processing). CBP1 produces two types of transcripts with different 3' ends: full-length 2.2-kb transcripts and 1.2-kb transcripts truncated within the coding sequence of Cbp1. Upon induction of respiration, the steady-state level of the long transcripts decreases while that of the short transcripts increases reciprocally, an unexpected result since the product of the long transcripts is required for COB mRNA stability and thus for respiration. Here we have tested the hypothesis that the short transcripts, or proteins translated from the short transcripts, are also required for respiration. A protein translated from the short transcripts was not detected by Western analysis, although polysome gradient fractions were shown to contain both long and short CBP1 transcripts. A mutant strain in which production of the short transcripts was abolished showed wild-type growth properties, indicating that the short transcripts are not required for respiration. Due to mutation of the carbon source-responsive element, the long transcript level in the mutant strain did not decrease during induction of respiration. The mutant strain had increased levels of COB RNA, suggestive that production of short CBP1 transcripts is a mechanism for downregulation of the levels of long CBP1 transcripts, Cbp1, and COB mRNA during the induction of respiration.
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PMID:Premature 3'-end formation of CBP1 mRNA results in the downregulation of cytochrome b mRNA during the induction of respiration in Saccharomyces cerevisiae. 923 77

Here, we report the complete nucleotide sequence of the 39 107-bp mitochondrial genome of the yeast Pichia sorbitophila. This genome is closely related to those of Candida parapsilosis and Debaryomyces hansenii, as judged from sequence similarities and synteny conservation. It encodes three subunits of cytochrome oxidase (COX1, COX2 and COX3), three subunits of ATP synthase (ATP6, ATP8 and ATP9), the seven subunits of NADH dehydrogenase (NAD1-6 and NAD4L), the apocytochrome b (COB), the large and small rRNAs and a complete set of tRNAs. Although the mitochondrial genome of P. sorbitophila contains the same core of mitochondrial genes observed in the ascomycetous yeasts, those coding for the RNAse P and the ribosomal protein VAR1p are missing. Moreover, the mtDNA of P. sorbitophila contains several introns in its genes and has the particularity of possessing an intron, which is not linked to any upstream exon.
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PMID:The complete mitochondrial genome of the yeast Pichia sorbitophila. 1959 28

Expression of the mitochondrially encoded ATP6 and ATP8 genes is translationally regulated by F1 ATPase. We report a translational repressor (Smt1p) of the ATP6/8 mRNA that, when mutated, restores translation of the encoded Atp6p and Atp8p subunits of the ATP synthase. Heterozygous smt1 mutants fail to rescue the translation defect, indicating that the mutations are recessive. Smt1p is an intrinsic inner membrane protein, which, based on its sedimentation, has a native size twice that of the monomer. Affinity purification of tagged Smt1p followed by reverse transcription of the associated RNA and PCR amplification of the resultant cDNA with gene-specific primers demonstrated the presence in mitochondria of Smt1p-ATP8/ATP6 and Smt1p-COB mRNA complexes. These results indicate that Smt1p is likely to be involved in translational regulation of both mRNAs. Applying Occam's principle, we favor a mechanistic model in which translation of the ATP8/ATP6 bicistronic mRNA is coupled to the availability of F1 for subsequent assembly of the Atp6p and Atp8p products into the ATP synthase. The mechanism of this regulatory pathway is proposed to entail a displacement of the repressor from the translationally mute Smt1-ATP8/ATP6 complex by F1, thereby permitting the Atp22p activator to interact with and promote translation of the mRNA.
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PMID:Regulation of mitochondrial translation of the ATP8/ATP6 mRNA by Smt1p. 2682 15