Differential regulation of the duplicated isocytochrome c genes in yeast

Journal Article · Sun Jul 01 04:00:00 EDT 1984 · Proc. Natl. Acad. Sci. U.S.A.; (United States)

DOI:https://doi.org/10.1073/pnas.81.14.4475· OSTI ID:5975842

Laz, T M; Pietras, D F; Sherman, F

The two unlinked genes CYC1 and CYC7 encode iso-1-cytochrome c and iso-2-cytochrome c, respectively, in the yeast Saccharomyces cerevisiae. An examination of the steady-state level of CYC1 and CYC7 mRNAs in normal and mutant strains grown under different conditions, along with previous results of apoprotein levels, demonstrate that CYC1 and CYC7 have similar and different modes of regulation. Both CYC1 and CYC7 mRNAs are diminished after anaerobic growth. In contrast, CYC1 mRNA but not CYC7 mRNA is decreased by heme deficiency in hem1 mutants. Although both CYC1 and CYC7 mRNAs are substantially lowered after growth in glucose medium, there is a difference in the kinetics of glucose derepression. CYC1 mRNA levels rise in the early logarithmic phase of growth before complete exhaustion of glucose, whereas CYC7 mRNA levels rise in the late logarithmic phase when the level of CYC1 mRNA has plateaued. For a brief period before cessation of growth, the level of CYC7 mRNA attains a level corresponding to the high derepressed level of CYC1 mRNA. The high amount of CYC7 mRNA is surprising because iso-2-cytochrome c constitutes only 5% of the total cytochrome c complement in derepressed cells. We suggest that iso-2-cytochrome c has the potential to comprise a major proportion of cytochrome c under certain physiologic conditions that have not been experimentally defined. The cyc3 mutant, which lacks the ability to attach heme groups to apocytochromes c, contains both CYC1 and CYC7 mRNAs in normal amounts. 39 references, 5 figures.

• Research Organization: Univ. of Rochester School of Medicine, NY
• DOE Contract Number: AC02-76EV03490
• OSTI ID: 5975842
• Journal Information: Proc. Natl. Acad. Sci. U.S.A.; (United States), Journal Name: Proc. Natl. Acad. Sci. U.S.A.; (United States) Vol. 81:14; ISSN PNASA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
ALDEHYDES
BIOCHEMICAL REACTION KINETICS
CARBOHYDRATES
CARBOXYLIC ACIDS
CYTOCHROMES
FUNGI
GENES
GLUCOSE
GROWTH
HEME
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HEXOSES
KINETICS
MESSENGER-RNA
MICROORGANISMS
MONOSACCHARIDES
MUTANTS
NUCLEIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PIGMENTS
PLANTS
PORPHYRINS
REACTION KINETICS
RNA
SACCHARIDES
SACCHAROMYCES
SACCHAROMYCES CEREVISIAE
STEADY-STATE CONDITIONS
YEASTS