Organization and expression of the COX6 genetic locus in<i>Saccharomyces cerevisiae</i>: multiple mRNAs with different 3' termini are transcribed from COX6 and regulated differentially

Wright, Richard M.; Rosenzweig, Bradley; Poyton, Robert O.

doi:10.1093/nar/17.3.1103

Cited by 23 publications

(18 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Strain JM43GD6 was constructed as follows. The COX6 gene in JM43 was disrupted by use of the plasmid pVISt3 (28), which is derived from pUC19. The URA3 gene was inserted into the HindIII site that is within the COX6 coding region on pVISt3 and the resulting plasmid was used to transform JM43 by the lithium acetate procedure (29).…”

Section: Methodsmentioning

confidence: 99%

Effects of Anoxia and the Mitochondrion on Expression of Aerobic Nuclear COX Genes in Yeast

Dagsgaard

Taylor

O’Brien

et al. 2001

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

Eucaryotic cells contain at least two general classes of oxygen-regulated nuclear genes: aerobic genes and hypoxic genes. Hypoxic genes are induced upon exposure to anoxia while aerobic genes are down-regulated. Recently, it has been reported that induction of some hypoxic nuclear genes in mammals and yeast requires mitochondrial respiration and that cytochrome-c oxidase functions as an oxygen sensor during this process. In this study, we have examined the role of the mitochondrion and cytochrome-c oxidase in the expression of yeast aerobic nuclear COX genes. We have found that the down-regulation of these genes in anoxic cells is reflected in reduced levels of their subunit polypeptides and that cytochrome-c oxidase subunits I, II, III, Vb, VI, VII, and VIIa are present in promitochondria from anoxic cells. By using nuclear cox mutants and mitochondrial rho 0 and mit ؊ mutants, we have found that neither respiration nor cytochrome-c oxidase is required for the down-regulation of these genes in cells exposed to anoxia but that a mitochondrial genome is required for their full expression under both normoxic and anoxic conditions. This requirement for a mitochondrial genome is unrelated to the presence or absence of a functional holocytochrome-c oxidase. We have also found that the down-regulation of these genes in cells exposed to anoxia and the down-regulation that results from the absence of a mitochondrial genome are independent of one another. These findings indicate that the mitochondrial genome, acting independently of respiration and oxidative phosphorylation, affects the expression of the aerobic nuclear COX genes and suggest the existence of a signaling pathway from the mitochondrial genome to the nucleus.

show abstract

Section: Methodsmentioning

confidence: 99%

Effects of Anoxia and the Mitochondrion on Expression of Aerobic Nuclear COX Genes in Yeast

Dagsgaard

Taylor

O’Brien

et al. 2001

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

show abstract

“…Insofar as the SNFJ gene product is a protein kinase (5), it is possible that SNFJ exerts its effect on SUC2 and other glucose-repressible genes through phosphorylation of the SSN6 gene product or other regulatory factors. address the question, we studied COX6, (25,26) and CYCI (11), the genes that encode cytochrome c oxidase subunit VI and iso-1-cytochrome c, respectively. Previous studies demonstrated that the transcription of both genes is glucose repressible in conjunction with the product of the HAP2 gene (11,23).…”

mentioning

confidence: 99%

“…Three hours following the shift, poly(A)+ RNA was prepared and Northern (RNA) blot analysis was conducted. The blots were hybridized with probes specific for the yeast actin gene (a nonresponding control), ORF-U (a divergently transcribed gene flanking COX6 upstream), or COX6 and ORF-D (a gene flanking COX6 downstream) (26). In the SNFI+ strain, both COX6 and ORF-U showed marked derepression (Fig.…”

mentioning

confidence: 99%

Release of two Saccharomyces cerevisiae cytochrome genes, COX6 and CYC1, from glucose repression requires the SNF1 and SSN6 gene products.

Wright¹,

Poyton²

1990

Mol. Cell. Biol.

View full text Add to dashboard Cite

We show here that SNF1 and SSN6 are required for derepression of the glucose-repressible yeast genes COX6 and CYC1, which encode the mitochondrial proteins cytochrome c oxidase subunit VI and iso-l-cytochrome c, respectively. In an snfl mutant genetic background, the transcription of both COX6 and CYC) continued to be repressed after cells were shifted into derepressing media. In an ssn6 mutant genetic background, both COX6 and CYCI were expressed constitutively at high levels in repressing media. SSN6 acted epistatically to SNFI in the regulation of both cytochrome genes. These findings are similar to previous findings on the effects of SNFI and SSN6 on SUC2 expression in Saccharomyces cerevisiae and are consistent with a model proposing that SNF1 exerts its effect through SSN6 on COX6 and CYCI.Yeast cells respond to growth in glucose by up-regulating fermentative metabolism, with the consequent production of ethanol. At the same time, enzymes in numerous metabolic pathways, including those involved in gluconeogenesis, the tricarboxylic acid cycle, and mitochondrial electron transport and oxidative phosphorylation (7, 9), are repressed. This process, referred to as glucose repression, is complex. It affects the activity of some enzymes and the synthesis of others (6-8, 13). For many genes, the effect of glucose repression on synthesis operates at the level of transcription (18,22) and is mediated by upstream cis-acting sites, i.e., upstream activation sequence elements (10,18,21,23).Through the isolation of nonrepressible and nonderepressible mutants and their suppressors, it has been possible to gain initial insight into the genetic regulation of glucose repression. Of the dozen or so genes so far implicated in glucose repression (1, 6-9, 13, 19), some of the best understood are SNFJ (CA TI, CCRI) and SSN6 (CYC8). The SNFJ gene (together with other SNF genes) (1-4, 15) is essential for sucrose fermentation because it is required for derepression of the synthesis of the secreted form of invertase, a product of SUC2. SNFJ also affects the derepression of a number of other glucose-repressible enzymes of intermediary metabolism; thus, it appears to be a global regulator of glucose repression (7,9 address the question, we studied COX6, (25, 26) and CYCI (11), the genes that encode cytochrome c oxidase subunit VI and iso-1-cytochrome c, respectively. Previous studies demonstrated that the transcription of both genes is glucose repressible in conjunction with the product of the HAP2 gene (11, 23). We report here that SNFI and SSN6 are also required for the release from glucose repression of COX6 and CYC1 and that they affect the transcription of these genes in a manner analogous to the way that they regulate SUC2.To determine whether SNFI is involved in COX6 regulation, we used an snfl deletion strain, MCY1595, and its parent carrying a wild-type SNFJ allele, MCY1093, kindly provided by Marian Carlson (Columbia University, New York, N.Y.). Cells were grown to the early log phase in 2% glucose, harvested, washed in H2...

show abstract

“…One class of S. cerevisiae genes that is now being subjected to intense investigation is that which encodes the mitochondrial respiratory proteins, particularly cytochrome c (13,14,19), cytochrome c oxidase (4,35,43,44,51,52), and coenzyme Q cytochrome c reductase (5,22,26). The intracellular level of each of these respiratory proteins is affected by carbon source (i.e., glucose repression) (30), oxygen tension (18), and heme availability (48).…”

mentioning

confidence: 99%

Identification of an upstream activation sequence and other cis-acting elements required for transcription of COX6 from Saccharomyces cerevisiae.

Trawick¹,

Rogness²,

Poyton³

1989

Mol. Cell. Biol.

View full text Add to dashboard Cite

show abstract

Organization and expression of the COX6 genetic locus inSaccharomyces cerevisiae: multiple mRNAs with different 3' termini are transcribed from COX6 and regulated differentially

Cited by 23 publications

References 34 publications

Effects of Anoxia and the Mitochondrion on Expression of Aerobic Nuclear COX Genes in Yeast

Effects of Anoxia and the Mitochondrion on Expression of Aerobic Nuclear COX Genes in Yeast

Release of two Saccharomyces cerevisiae cytochrome genes, COX6 and CYC1, from glucose repression requires the SNF1 and SSN6 gene products.

Identification of an upstream activation sequence and other cis-acting elements required for transcription of COX6 from Saccharomyces cerevisiae.

Contact Info

Product

Resources

About