The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)



Gene Review

CYC7  -  cytochrome c isoform 2

Saccharomyces cerevisiae S288c

Synonyms: CYP3, Cytochrome c iso-2, YEL039C
Welcome! If you are familiar with the subject of this article, you can contribute to this open access knowledge base by deleting incorrect information, restructuring or completely rewriting any text. Read more.

High impact information on CYC7

  • The CYC1 and CYC7 sites compete for binding to HAP1 and have comparable affinities for the protein [1].
  • The deletion apparently fuses a new regulatory region to the structural portion of the CYC7 locus [2].
  • Cloning of the ROAM mutant gene CYC7-H2 shows that a 5.5 kb sequence homologous to a transposable and reiterated Ty1 element is inserted in the 5' noncoding region of the CYC7 structural locus [3].
  • The expression of the yeast CYC1 and CYC7 genes is controlled by the HAP1 activator [4].
  • To analyze how HAP1 binds to UAS1 and CYC7, we performed saturation mutagenesis of the DNA-binding domain and recovered mutants with altered activity [4].

Biological context of CYC7

  • Deletion analysis of the CYC7 regulatory region suggested that three STRE elements were each capable of inducing the stress response [5].
  • The aer2 mutations also caused a large increase in CYC7 gene expression under all conditions; this gene is subject to heme activation/repression, as well as catabolite repression [6].
  • Furthermore, Ala substitutions in the dimerization element selectively diminished transcriptional activation at UAS/CYC7 [7].
  • Moreover, we show that activity of HAP1 mutants defective for activation of the CYC7gene is restored by specific mutations in the CYC7 binding site [8].
  • The CYC1 locus was previously shown to be on the right arm of chromosome X, and the CYC7 locus is shown in this investigation to be on the left arm of chromosome V closely linked to the min1 and mak10 markers [9].

Associations of CYC7 with chemical compounds

  • The CYC7 gene, encoding iso-2-cytochrome c, has been demonstrated to respond to heat shock, glucose starvation, approach-to-stationary phase, and, as we demonstrate here, to osmotic stress [5].
  • The hypoxic genes COX5b and CYC7 are not expressed until the oxygen concentration is below 0.5 microM O2 [10].
  • We have found that carbon monoxide (CO) completely blocks the anoxia-induced expression of two hypoxic genes, OLE1 and CYC7, partially blocks the induction of a third gene, COX5b, and has no effect on the expression of other hypoxic or aerobic genes [11].
  • Mitochondrial NO production in yeast is influenced by the YHb flavohemoglobin NO oxidoreductase, stimulates expression of the hypoxic nuclear gene CYC7, and is accompanied by an increase in protein tyrosine nitration [12].
  • The mutated phenotype that commutes the expression of the two isocytochrome structural genes (superactivation of CYP3 and inhibition of CYC1) results from a transversion in an AGT codon (serine) in the wild-type to an AGG codon (arginine) in the mutant [13].

Physical interactions of CYC7

  • In a separate experiment, we generate a mutation in the DNA-binding domain of HAP1 that requires the addition of zinc for binding to either UAS1 or CYC7 in vitro [14].

Regulatory relationships of CYC7

  • The ROX3 gene was identified during a hunt for mutants with increased expression of the heme-regulated CYC7 gene, which encodes the minor species of cytochrome c in the yeast Saccharomyces cerevisiae [15].

Other interactions of CYC7

  • In Saccharomyces cerevisiae, expression of cytochrome c, encoded by CYC1 and CYC7, is required not only for electron transfer but also for COX assembly through a still unknown mechanism [16].
  • Mutations in the ROX3 gene prevented CYC7 RNA accumulation during heat shock and osmotic stress [5].
  • Deletion of RTS1 caused temperature and osmotic sensitivity and increased accumulation of CYC7 RNA under all conditions [5].
  • Cyp1p (Hap1p) activates, among others, the two structural genes, CYC1 and CYP3 (CYC7) which encode isocytochromes c in Saccharomyces cerevisiae [17].
  • ROX1 encodes a heme-induced repression factor regulating ANB1 and CYC7 of Saccharomyces cerevisiae [18].

Analytical, diagnostic and therapeutic context of CYC7

  • We tested this hypothesis via oligonucleotide-directed mutagenesis, by placing the sequence CAAG, a member of one of these consensus sequences, upstream of the coding sequence of the CYC7 gene at a site at which initiation does not occur [19].
  • This PCR fragment was used as a probe to isolate CYP3 genomic and cDNA clones.(ABSTRACT TRUNCATED AT 250 WORDS)[20]


  1. Yeast HAP1 activator binds to two upstream activation sites of different sequence. Pfeifer, K., Prezant, T., Guarente, L. Cell (1987) [Pubmed]
  2. An extensive deletion causing overproduction of yeast iso-2-cytochrome c. McKnight, G.L., Cardillo, T.S., Sherman, F. Cell (1981) [Pubmed]
  3. Mating signals control expression of mutations resulting from insertion of a transposable repetitive element adjacent to diverse yeast genes. Errede, B., Cardillo, T.S., Sherman, F., Dubois, E., Deschamps, J., Wiame, J.M. Cell (1980) [Pubmed]
  4. HAP1 positive control mutants specific for one of two binding sites. Turcotte, B., Guarente, L. Genes Dev. (1992) [Pubmed]
  5. Rox3 and Rts1 function in the global stress response pathway in baker's yeast. Evangelista, C.C., Rodriguez Torres, A.M., Limbach, M.P., Zitomer, R.S. Genetics (1996) [Pubmed]
  6. A yeast protein with homology to the beta-subunit of G proteins is involved in control of heme-regulated and catabolite-repressed genes. Zhang, M., Rosenblum-Vos, L.S., Lowry, C.V., Boakye, K.A., Zitomer, R.S. Gene (1991) [Pubmed]
  7. The coiled coil dimerization element of the yeast transcriptional activator Hap1, a Gal4 family member, is dispensable for DNA binding but differentially affects transcriptional activation. Hach, A., Hon, T., Zhang, L. J. Biol. Chem. (2000) [Pubmed]
  8. Mutations in target DNA elements of yeast HAP1 modulate its transcriptional activity without affecting DNA binding. Ha, N., Hellauer, K., Turcotte, B. Nucleic Acids Res. (1996) [Pubmed]
  9. Chromosome mapping of the CYC7 gene determining yeast iso-2-cytochrome c: structural and regulatory regions. Sherman, F., Stewart, J.W., Helms, C., Downie, J.A. Proc. Natl. Acad. Sci. U.S.A. (1978) [Pubmed]
  10. Effects of oxygen concentration on the expression of cytochrome c and cytochrome c oxidase genes in yeast. Burke, P.V., Raitt, D.C., Allen, L.A., Kellogg, E.A., Poyton, R.O. J. Biol. Chem. (1997) [Pubmed]
  11. Oxygen sensing in yeast: evidence for the involvement of the respiratory chain in regulating the transcription of a subset of hypoxic genes. Kwast, K.E., Burke, P.V., Staahl, B.T., Poyton, R.O. Proc. Natl. Acad. Sci. U.S.A. (1999) [Pubmed]
  12. Mitochondrial cytochrome oxidase produces nitric oxide under hypoxic conditions: implications for oxygen sensing and hypoxic signaling in eukaryotes. Castello, P.R., David, P.S., McClure, T., Crook, Z., Poyton, R.O. Cell metabolism. (2006) [Pubmed]
  13. CYP1 (HAP1) regulator of oxygen-dependent gene expression in yeast. II. Missense mutation suggests alternative Zn fingers as discriminating agents of gene control. Verdière, J., Gaisne, M., Guiard, B., Defranoux, N., Slonimski, P.P. J. Mol. Biol. (1988) [Pubmed]
  14. Internal deletions in the yeast transcriptional activator HAP1 have opposite effects at two sequence elements. Kim, K.S., Pfeifer, K., Powell, L., Guarente, L. Proc. Natl. Acad. Sci. U.S.A. (1990) [Pubmed]
  15. The ROX3 gene encodes an essential nuclear protein involved in CYC7 gene expression in Saccharomyces cerevisiae. Rosenblum-Vos, L.S., Rhodes, L., Evangelista, C.C., Boayke, K.A., Zitomer, R.S. Mol. Cell. Biol. (1991) [Pubmed]
  16. Cytochrome oxidase assembly does not require catalytically active cytochrome C. Barrientos, A., Pierre, D., Lee, J., Tzagoloff, A. J. Biol. Chem. (2003) [Pubmed]
  17. Characterization of a promoter mutation in the CYP3 gene of Saccharomyces cerevisiae which cancels regulation by Cyp1p (Hap1p) without affecting its binding site. Lodi, T., Petrochilo, E., Gaisne, M., Verdière, J. Mol. Gen. Genet. (1996) [Pubmed]
  18. ROX1 encodes a heme-induced repression factor regulating ANB1 and CYC7 of Saccharomyces cerevisiae. Lowry, C.V., Zitomer, R.S. Mol. Cell. Biol. (1988) [Pubmed]
  19. A sequence that directs transcriptional initiation in yeast. Healy, A.M., Zitomer, R.S. Curr. Genet. (1990) [Pubmed]
  20. The yeast cyclophilin multigene family: purification, cloning and characterization of a new isoform. McLaughlin, M.M., Bossard, M.J., Koser, P.L., Cafferkey, R., Morris, R.A., Miles, L.M., Strickler, J., Bergsma, D.J., Levy, M.A., Livi, G.P. Gene (1992) [Pubmed]
WikiGenes - Universities