Yeast RPO41 gene product is required for transcription and maintenance of the mitochondrial genome.

Greenleaf, Arno L.; Kelly, Jeffrey L.; Lehman, I. R.

doi:10.1073/pnas.83.10.3391

Cited by 139 publications

(69 citation statements)

References 34 publications

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“…9A, lanes 1 (32). The products of these nuclear genes are required for mitochondrial gene transcription and maintenance of the intact mitochondrial genome (15,25,40). It has been reported that RP041 transcript levels and the core polymerase activity increase about fivefold in glycerol, and it has been suggested that the increase in mitochondrial transcript abundance described above may be due to this increase in RP041 levels (42,62 (59).…”

Section: Resultsmentioning

confidence: 99%

Glucose repression of yeast mitochondrial transcription: kinetics of derepression and role of nuclear genes.

Ulery¹,

Jang²,

Jaehning³

1994

Mol. Cell. Biol.

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Yeast mitochondrial transcript and gene product abundance has been observed to increase upon release from glucose repression, but the mechanism of regulation of this process has not been determined. We report a kinetic analysis of this phenomenon, which demonstrates that the abundance of all classes of mitochondrial RNA changes slowly relative to changes observed for glucose-repressed nuclear genes. Several cell doublings are required to achieve the 2-to 20-fold-higher steady-state levels observed after a shift to a nonrepressing carbon source. Although we observed that in some yeast strains the mitochondrial DNA copy number also increases upon derepression, this does not seem to play the major role in increased RNA abundance. Instead we found that three-to sevenfold increases in RNA synthesis rates, measured by in vivo pulse-labelling experiments, do correlate with increased transcript abundance. We found that mutations in the SNF1 and REG] genes, which are known to affect the expression of many nuclear genes subject to glucose repression, affect derepression of mitochondrial transcript abundance. These genes do not appear to regulate mitochondrial transcript levels via regulation of the nuclear genes RP041 and MTF1, which encode the subunits of the mitochondrial RNA polymerase. We conclude that a nuclear gene-controlled factor(s) in addition to the two RNA polymerase subunits must be involved in glucose repression of mitochondrial transcript abundance.Mitochondria are the site of many complex biochemical processes, including the citric acid cycle, oxidative phosphorylation, and electron transport (reviewed in reference 1). In addition to these processes, the organelles maintain their own genomes and transcribe and synthesize the proteins they encode (reviewed in references 7 and 33). In addition to being dependent on the organelle-encoded gene products, mitochondria are functionally dependent upon many genes encoded in the nuclear genome for all of these processes. Mitochondrial activity in the yeast Saccharomyces cerevisiae is subject to regulation; under repressing conditions, such as anaerobic growth or growth on glucose, mitochondrial activity is minimal. However, under derepressing conditions, such as growth on a nonfermentable carbon source, mitochondrial activity is high and the requirement for mitochondrial enzymes increases (7,26). Since expression of the mitochondrial genes is dependent on nuclear genes, coordinated regulation of expression of the nuclear and mitochondrial genomes must be involved in these changes.It is well documented that glucose repression is a major regulatory system in yeast cells and affects a large number of nuclear genes and gene products (reviewed in references 35 and 36). It has also been shown that glucose repression affects the mitochondrion in several ways. The expression of many nucleus-encoded mitochondrial genes is glucose repressed at the levels of transcription and RNA stability (reviewed in references 20, 35, and 36). pressed cells (reviewed in references 7 and 33)...

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Section: Resultsmentioning

confidence: 99%

Glucose repression of yeast mitochondrial transcription: kinetics of derepression and role of nuclear genes.

Ulery¹,

Jang²,

Jaehning³

1994

Mol. Cell. Biol.

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“…The comprehensively studied T7 RNAP can recognize specific promoter sequences, correctly initiate transcription, and catalyze transcript elongation until termination unaided by auxiliary proteins (reviewed in Cheetham and Steitz, 2000). In mitochondria of the budding yeast Saccharomyces cerevisiae (Greenleaf et al, 1986;Masters et al, 1987), mammals (Tiranti et al, 1997;Falkenberg et al, 2002;Gaspari et al, 2004), and other eukaryotic organisms (Cermakian et al, 1996), a nuclear-encoded T7 phage-type RNAP has replaced the ancestral bacterial-type RNAP. Transcription initiation in the mitochondria of yeast and mammals, however, depends on the transcriptional cofactor mtTFB (MTF1, TFBM), which is related to rRNA dimethyladenosine transferases (Winkley et al, 1985;Schinkel et al, 1987;Falkenberg et al, 2002;McCulloch et al, 2002;Matsunaga and Jaehning, 2004b).…”

Section: Introductionmentioning

confidence: 99%

Arabidopsis Phage-Type RNA Polymerases: Accurate in Vitro Transcription of Organellar Genes

Kühn¹,

Bohne²,

Liere

et al. 2007

The Plant Cell

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The T7 bacteriophage RNA polymerase (RNAP) performs all steps of transcription, including promoter recognition, initiation, and elongation as a single-polypeptide enzyme. Arabidopsis thaliana possesses three nuclear-encoded T7 phage-type RNAPs that localize to mitochondria (RpoTm), plastids (RpoTp), or presumably both organelles (RpoTmp). Their specific functions are as yet unresolved. We have established an in vitro transcription system to examine the abilities of the three Arabidopsis phage-type RNAPs to synthesize RNA and to recognize organellar promoters. All three RpoT genes were shown to encode transcriptionally active RNAPs. RpoTmp displayed no significant promoter specificity, whereas RpoTm and RpoTp were able to accurately initiate transcription from overlapping subsets of mitochondrial and plastidial promoters without the aid of protein cofactors. Our study strongly suggests RpoTm to be the enzyme that transcribes most, if not all, mitochondrial genes in Arabidopsis. Intrinsic promoter specificity, a feature that RpoTm and RpoTp share with the T7 RNAP, appears to have been conserved over the long period of evolution of nuclear-encoded mitochondrial and plastidial RNAPs. Selective promoter recognition by the Arabidopsis phage-type RNAPs in vitro implies that auxiliary factors are required for efficient initiation of transcription in vivo.

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“…The reaction mixture was incubated at 37°C for 1 to 1.5 h at 37°C and passed over a Sephadex G-50 spin column to remove unincorporated rNTPs, and the RNA was precipitated with ethanol. RNA was 3' end labeled in a 20-,ul reaction mixture containing 50 mM N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES; pH 7.5), 15 Tn:URA3), whose construction has been described in detail elsewhere (15). Yeast cells were grown to mid-to late logarithmic phase at 30°C in a medium containing 2% Bacto Peptone, 1% yeast extract, and an appropriate carbon source, either 2% glucose (YPD) or 2% galactose (YPGAL).…”

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confidence: 99%

Saccharomyces cerevisiae contains an RNase MRP that cleaves at a conserved mitochondrial RNA sequence implicated in replication priming.

Stohl

Clayton

1992

Mol. Cell. Biol.

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The overall mode of mitochondrial DNA (mtDNA) replication is best understood for the mouse and human systems, and a general model of vertebrate mtDNA replication has been established (9). Mammalian mtDNA replicates by unidirectional synthesis from two distinct origins, the origin of heavy-strand replication and the origin of light-strand replication, which are located two-thirds of the genomic distance apart on the closed circle. The structural features and mechanisms of RNA priming are very different at these two origins (3,7,9,29,30). A characteristic hallmark of the origin of heavy-strand replication is the presence of three evolutionarily conserved sequence blocks (CSBs I, II, and III) at or near the 5' ends of newly synthesized heavy strands. It has been demonstrated for nearly all 5' ends of nascent heavy-strand DNAs that there are RNA species whose 3' ends map immediately adjacent to the DNA 5' ends. It has also been shown that 5' ends of these RNAs map at the initiation site of transcription from the major lightstrand promoter (3, 7). On the basis of these and other findings, Chang and coworkers hypothesized that transcripts from this promoter play a role in heavy-strand replication by serving as primers for DNA synthesis and that individual primer termini were generated by processing of a primary transcript (3, 7).Mammalian complementary to the origin of leading heavy-strand mtDNA replication (4, 6, 28). The endonuclease activity is present in both nuclear and mitochondrial fractions (2,5,14,17,28) and has been proposed to participate in mitochondrial primer RNA metabolism in vivo. The standard mitochondrial RNA (mtRNA) substrate for mouse and human RNase MRPs contains three short regions of sequence that are highly conserved in vertebrate species (CSBs I, II, and III). Initial characterization of the mouse RNase MRP activity demonstrated that the site-specific cleavage of mtRNA substrate in vitro occurred immediately adjacent to CSB II, and it was postulated that CSB II played a role in cleavage site specificity (4). Subsequent deletional analysis and saturation mutagenesis have determined basic substrate requirements for cleavage by mouse RNase MRP; CSB II and CSB III are essential for both efficient and accurate cleavage, whereas CSB I is not (2).In contrast to the mammalian system, our knowledge of yeast wild-type mtDNA replication initiation, at the molecular level, is less advanced. However, studies with hypersuppressive petite strains indicate that putative yeast mitochondrial replication origins (on [or rep {reference 12 and references therein}] sequences) are characterized by a 300-bp A+T-rich segment containing the following regions: a 16-bp A+T-rich sequence containing an active promoter for transcription initiation (termed r), a 17-bp GC cluster C located immediately downstream of the promoter, a central 200-bp A+T-rich stretch (termed C), and GC clusters A and B, which are separated by an A+T-rich region (1, 10, 13). It has also been proposed that the active on sequences of yeast mtDNA are ...

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Yeast RPO41 gene product is required for transcription and maintenance of the mitochondrial genome.

Cited by 139 publications

References 34 publications

Glucose repression of yeast mitochondrial transcription: kinetics of derepression and role of nuclear genes.

Glucose repression of yeast mitochondrial transcription: kinetics of derepression and role of nuclear genes.

Arabidopsis Phage-Type RNA Polymerases: Accurate in Vitro Transcription of Organellar Genes

Saccharomyces cerevisiae contains an RNase MRP that cleaves at a conserved mitochondrial RNA sequence implicated in replication priming.

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