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

CYC1  -  cytochrome c isoform 1

Saccharomyces cerevisiae S288c

Synonyms: Cytochrome c iso-1, J1653, YJR048W
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.

Disease relevance of CYC1


High impact information on CYC1

  • A similar effect was found at the ADH1 locus, establishing that this effect is not cyc1 gene-specific [6].
  • Mutations in the Saccharomyces cerevisiae SUA7 gene were isolated as suppressors of an aberrant ATG translation initiation codon in the leader region of the cyc1 gene [6].
  • Strikingly, this sequence bears no obvious similarity to the sequence bound by HAP1 at UAS1 of the CYC1 gene [7].
  • Transcriptional activation by the yeast CYC1 upstream activation site UAS2UP1 requires the products of both the HAP2 and HAP3 regulatory genes [8].
  • A single near-consensus synthetic 17 bp oligonucleotide, installed in front of the yeast GAL1 or CYC1 transcription units, conferred a high level of galactose inducibility upon these genes [9].

Chemical compound and disease context of CYC1


Biological context of CYC1

  • A GAL4-like zinc finger (residues 1-148) specifies binding to the dissimilar sites UAS1 (of CYC1) and CYC7, and an acidic domain (residues 1307-1483) is essential for activation of transcription [12].
  • This study investigates the overproduction of the CYP1 protein when the CYP1(HAP1) gene is placed under the control of the GAL10-CYC1 hybrid promoter (either at the locus of the CYP1(HAP1) gene or cloned in a high-copy-number plasmid) [13].
  • Although both CYC1 and CYC7 mRNAs are substantially lowered after growth in glucose medium, there is a difference in the kinetics of glucose derepression [14].
  • CYC1 and sup4 are part of a tightly linked cluster of genes on chromosome X in the yeast Saccharomyces cerevisiae [15].
  • The physical mapping has allowed unambiguous determination of the orientation of CYC1 and sup4 relative to each other, the centromere, and a nearby transfer ribonucleic acid (tRNA(2Ser)) gene [15].

Anatomical context of CYC1

  • However, in contrast to the normal CYC1+ mRNA that is associated mainly with four to seven ribosomes, the bulk of the CYC1-239-O mRNA is associated with one to four ribosomes [16].
  • CYC1 mRNA distribution on polyribosomes confirmed that only ATG codons within the initiation region were translated at high efficiency [17].
  • Current work on degradation of proteins in mitochondria, on degradation of mRNA in the nucleus, and on N-terminal acetylation stems from properties of CYC1 mutants isolated in early screens more than a decade ago [18].

Associations of CYC1 with chemical compounds

  • For others (COX5a and CYC1) the level of expression is nearly constant between 200 microM O2 and their threshold and then drops off [19].
  • 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 [20].
  • Though the CYC1 promoter is fully induced in yeast grown in glycerol medium, UASC-GAL chimeric promoters containing UASG were repressed as much as 400-fold (UASC-GAL1) or 1350-fold (UASC-GAL10) in this growth medium [21].
  • NMR analysis of CYP1(HAP1) DNA binding domain-CYC1 upstream activation sequence interactions: recognition of a CGG trinucleotide and of an additional thymine 5 bp downstream by the zinc cluster and the N-terminal extremity of the protein [22].
  • Attempts to increase production by addition of IPTG suppressed the number of copies of the CYC1 gene within the population [1].

Physical interactions of CYC1

  • First, while CYC1 contains two sites that bind HAP1 cooperatively, CYT1 has a single high-affinity site [23].
  • The binding of HAP1 to the CYT1 element was studied in detail and found to differ in two important respects from binding to the CYC1 element [23].
  • When oligonucleotides containing a REB1-binding site are placed between the CYC1 upstream activating sequence and TATA box, transcription by RNA polymerase II in vivo is substantially reduced, suggesting that REB1 acts as a repressor of RNA polymerase II transcription [24].
  • The ABF1 binding sites also acted in an orientation-independent manner when a synthetic ABF1 binding site was inserted into the yeast CYC1 gene lacking its transcriptional activation region [25].
  • A LexA-Gln3 fusion protein supported transcriptional activation when bound to one or more LexAp binding sites upstream of a minimal CYC1-derived promoter devoid of UAS elements [26].

Regulatory relationships of CYC1

  • The CYC1 gene of Saccharomyces cerevisiae is positively regulated by the HAP2 and HAP3 proteins, which form a heteromeric complex that binds to a CCAAT box in the upstream activation site, UAS2, and which activate transcription in a nonfermentable carbon source [27].
  • The predicted presence of large helical structural variation in yeast HIS4 upstream region is correlated with general amino acid control on the CYC1 gene [28].
  • Hap1 is a yeast transcriptional activator which controls expression of genes such as CYC1 and CYC7 [29].
  • The ENO1 URS element repressed transcription of the yeast CYC1 gene when positioned between the CYC1 upstream activation sequences (UAS elements) and TATAAA boxes [30].
  • The ROX1 locus of S. cerevisiae is known to regulate CYC1, COXVb, and ANB1 genes at the transcriptional level; the ROX1 locus thus regulates all known anaerobically expressed genes that are involved in different cellular functions such as respiration and protein synthesis [31].

Other interactions of CYC1

  • The expression of the yeast CYC1 and CYC7 genes is controlled by the HAP1 activator [12].
  • The TFIIB mutations conferred downstream shifts in transcription initiation at the ADH1 and CYC1 promoters, whereas no significant shifts were observed at the HIS3 promoter [32].
  • Nonetheless, essential signals have seemed to be confined to compact regions in vivo, and we find that a short RNA with only 70 bases of GAL7 sequence upstream and 8 to 10 bases downstream of the poly(A) addition site is processed in vitro, as is an analogous CYC1 pre-RNA [33].
  • In an ssn6 mutant genetic background, both COX6 and CYC1 were expressed constitutively at high levels in repressing media [34].
  • The mutator gene DEL1 in the yeast Saccharomyces cerevisiae causes a high rate of formation of multisite mutations that encompass the following three adjacent genes: CYC1, which determines the structure of iso-1-cytochrome c; RAD7, which controls UV sensitivity; and OSM1, which controls osomotic sensitivity [35].

Analytical, diagnostic and therapeutic context of CYC1

  • Ligation of the 18 bp element into a plasmid carrying the CYC1 promoter deleted UAS-activated transcription and conferred transcriptional repression by unsaturated fatty acids [36].
  • CAR1 DNA fragments containing the yeast CAR1 gene sequences from the transcription initiation site (-49) or translation initiation site (+1) to the +501 region were amplified using PCR and inversely fused to the yeast CYC1 promoter on the yeast YIp5 plasmid [37].
  • Dissection of the upstream activation site 1 (UAS1) of the yeast CYC1 gene showed that the A and B regions respond individually to regulation by the HAP1 protein, and that a point mutation in the B region converts this region to a translation upstream factor (TUF)-regulated element [38].
  • Site-directed mutagenesis in and adjacent to the 38-bp region was used to identify signals involved in the formation and positioning of CYC1 mRNA 3' ends [39].
  • Yeast cytochrome c messenger RNA. In vitro translation and specific immunoprecipitation of the CYC1 gene product [40].


  1. Bacterial expression of a mitochondrial cytochrome c. Trimethylation of lys72 in yeast iso-1-cytochrome c and the alkaline conformational transition. Pollock, W.B., Rosell, F.I., Twitchett, M.B., Dumont, M.E., Mauk, A.G. Biochemistry (1998) [Pubmed]
  2. Bidirectional binding of the TATA box binding protein to the TATA box. Cox, J.M., Hayward, M.M., Sanchez, J.F., Gegnas, L.D., van der Zee, S., Dennis, J.H., Sigler, P.B., Schepartz, A. Proc. Natl. Acad. Sci. U.S.A. (1997) [Pubmed]
  3. Yeast TATA-binding protein TFIID binds to TATA elements with both consensus and nonconsensus DNA sequences. Hahn, S., Buratowski, S., Sharp, P.A., Guarente, L. Proc. Natl. Acad. Sci. U.S.A. (1989) [Pubmed]
  4. Expression cassettes for formaldehyde and fluoroacetate resistance, two dominant markers in Saccharomyces cerevisiae. van den Berg, M.A., Steensma, H.Y. Yeast (1997) [Pubmed]
  5. Comparison of expression of the endo-beta-1,3-1,4-glucanase gene from Bacillus subtilis in Saccharomyces cerevisiae from the CYC1 and ADH1 promoters. Cantwell, B.A., Brazil, G., Murphy, N., McConnell, D.J. Curr. Genet. (1986) [Pubmed]
  6. The yeast SUA7 gene encodes a homolog of human transcription factor TFIIB and is required for normal start site selection in vivo. Pinto, I., Ware, D.E., Hampsey, M. Cell (1992) [Pubmed]
  7. Yeast HAP1 activator binds to two upstream activation sites of different sequence. Pfeifer, K., Prezant, T., Guarente, L. Cell (1987) [Pubmed]
  8. Yeast HAP2 and HAP3 activators both bind to the CYC1 upstream activation site, UAS2, in an interdependent manner. Olesen, J., Hahn, S., Guarente, L. Cell (1987) [Pubmed]
  9. Specific DNA binding of GAL4, a positive regulatory protein of yeast. Giniger, E., Varnum, S.M., Ptashne, M. Cell (1985) [Pubmed]
  10. DNA sequence of a mutation in the leader region of the yeast iso-1-cytochrome c mRNA. Stiles, J.I., Szostak, J.W., Young, A.T., Wu, R., Consaul, S., Sherman, F. Cell (1981) [Pubmed]
  11. Expression of functional chicken oviduct progesterone receptors in yeast (Saccharomyces cerevisiae). Mak, P., McDonnell, D.P., Weigel, N.L., Schrader, W.T., O'Malley, B.W. J. Biol. Chem. (1989) [Pubmed]
  12. HAP1 positive control mutants specific for one of two binding sites. Turcotte, B., Guarente, L. Genes Dev. (1992) [Pubmed]
  13. Evidence for an interaction between the CYP1(HAP1) activator and a cellular factor during heme-dependent transcriptional regulation in the yeast Saccharomyces cerevisiae. Fytlovich, S., Gervais, M., Agrimonti, C., Guiard, B. EMBO J. (1993) [Pubmed]
  14. Differential regulation of the duplicated isocytochrome c genes in yeast. Laz, T.M., Pietras, D.F., Sherman, F. Proc. Natl. Acad. Sci. U.S.A. (1984) [Pubmed]
  15. Physical analysis of the CYC1-sup4 interval in Saccharomyces cerevisiae. Shalit, P., Loughney, K., Olson, M.V., Hall, B.D. Mol. Cell. Biol. (1981) [Pubmed]
  16. A mutation allowing an mRNA secondary structure diminishes translation of Saccharomyces cerevisiae iso-1-cytochrome c. Baim, S.B., Pietras, D.F., Eustice, D.C., Sherman, F. Mol. Cell. Biol. (1985) [Pubmed]
  17. Initiation of translation can occur only in a restricted region of the CYC1 mRNA of Saccharomyces cerevisiae. Yun, D.F., Sherman, F. Mol. Cell. Biol. (1995) [Pubmed]
  18. The importance of mutation, then and now: studies with yeast cytochrome c. Sherman, F. Mutat. Res. (2005) [Pubmed]
  19. 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]
  20. 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]
  21. GAL1-GAL10 divergent promoter region of Saccharomyces cerevisiae contains negative control elements in addition to functionally separate and possibly overlapping upstream activating sequences. West, R.W., Chen, S.M., Putz, H., Butler, G., Banerjee, M. Genes Dev. (1987) [Pubmed]
  22. NMR analysis of CYP1(HAP1) DNA binding domain-CYC1 upstream activation sequence interactions: recognition of a CGG trinucleotide and of an additional thymine 5 bp downstream by the zinc cluster and the N-terminal extremity of the protein. Vuidepot, A.L., Bontems, F., Gervais, M., Guiard, B., Shechter, E., Lallemand, J.Y. Nucleic Acids Res. (1997) [Pubmed]
  23. Regulation of the yeast CYT1 gene encoding cytochrome c1 by HAP1 and HAP2/3/4. Schneider, J.C., Guarente, L. Mol. Cell. Biol. (1991) [Pubmed]
  24. Identification of a Saccharomyces cerevisiae DNA-binding protein involved in transcriptional regulation. Wang, H., Nicholson, P.R., Stillman, D.J. Mol. Cell. Biol. (1990) [Pubmed]
  25. Transcriptional control of the Saccharomyces cerevisiae ADH1 gene by autonomously replicating sequence binding factor 1. Yoo, H.Y., Jung, S.Y., Kim, Y.H., Kim, J., Jung, G., Rho, H.M. Curr. Microbiol. (1995) [Pubmed]
  26. G1n3p is capable of binding to UAS(NTR) elements and activating transcription in Saccharomyces cerevisiae. Cunningham, T.S., Svetlov, V.V., Rai, R., Smart, W., Cooper, T.G. J. Bacteriol. (1996) [Pubmed]
  27. Identification and characterization of HAP4: a third component of the CCAAT-bound HAP2/HAP3 heteromer. Forsburg, S.L., Guarente, L. Genes Dev. (1989) [Pubmed]
  28. The predicted presence of large helical structural variation in yeast HIS4 upstream region is correlated with general amino acid control on the CYC1 gene. Nussinov, R. J. Biomol. Struct. Dyn. (1985) [Pubmed]
  29. Fusions with histone H3 result in highly specific alteration of gene expression. Ha, N., Hellauer, K., Turcotte, B. Nucleic Acids Res. (2000) [Pubmed]
  30. Transcriptional regulation by an upstream repression sequence from the yeast enolase gene ENO1. Carmen, A.A., Brindle, P.K., Park, C.S., Holland, M.J. Yeast (1995) [Pubmed]
  31. The ANB1 locus of Saccharomyces cerevisiae encodes the protein synthesis initiation factor eIF-4D. Mehta, K.D., Leung, D., Lefebvre, L., Smith, M. J. Biol. Chem. (1990) [Pubmed]
  32. Promoter-specific shifts in transcription initiation conferred by yeast TFIIB mutations are determined by the sequence in the immediate vicinity of the start sites. Faitar, S.L., Brodie, S.A., Ponticelli, A.S. Mol. Cell. Biol. (2001) [Pubmed]
  33. Unusual aspects of in vitro RNA processing in the 3' regions of the GAL1, GAL7, and GAL10 genes in Saccharomyces cerevisiae. Sadhale, P.P., Platt, T. Mol. Cell. Biol. (1992) [Pubmed]
  34. Release of two Saccharomyces cerevisiae cytochrome genes, COX6 and CYC1, from glucose repression requires the SNF1 and SSN6 gene products. Wright, R.M., Poyton, R.O. Mol. Cell. Biol. (1990) [Pubmed]
  35. A mutator affecting the region of the iso-1-cytochrome c gene in yeast. Liebman, S.W., Singh, A., Sherman, F. Genetics (1979) [Pubmed]
  36. Molecular mechanism of the multiple regulation of the Saccharomyces cerevisiae ATF1 gene encoding alcohol acetyltransferase. Fujiwara, D., Kobayashi, O., Yoshimoto, H., Harashima, S., Tamai, Y. Yeast (1999) [Pubmed]
  37. Antisense-mediated inhibition of arginase (CAR1) gene expression in Saccharomyces cerevisiae. Park, H., Shin, M., Woo, I. J. Biosci. Bioeng. (2001) [Pubmed]
  38. A point mutation in the CYC1 UAS1 creates a new combination of regulatory elements that activate transcription synergistically. Sousa, R., Arcangioli, B. EMBO J. (1989) [Pubmed]
  39. Signals that produce 3' termini in CYC1 mRNA of the yeast Saccharomyces cerevisiae. Russo, P., Li, W.Z., Guo, Z., Sherman, F. Mol. Cell. Biol. (1993) [Pubmed]
  40. Yeast cytochrome c messenger RNA. In vitro translation and specific immunoprecipitation of the CYC1 gene product. Zitomer, R.S., Hall, B.D. J. Biol. Chem. (1976) [Pubmed]
WikiGenes - Universities