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Oxygen sensing in yeast evidence for the ... on of a subset of hypoxic genes
Oxygen sensing in yeast: evidence for the involvement of the respiratory chain in regulating the transcription of a subset of hypoxic genes.
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Oxygen availability affects the transcription of a number of genes in nearly all organisms. Although the molecular mechanisms for sensing oxygen are not precisely known, heme is thought to play a pivotal role. Here, we address the possibility that oxygen sensing in yeast, as in mammals, involves a redox-sensitive hemoprotein. 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. In addition, transition metals (Co and Ni) induce the expression of OLE1 and CYC7 in a concentration-dependent manner under aerobic conditions. These findings suggest that the redox state of an oxygen-binding hemoprotein is involved in controlling the expression of at least two hypoxic yeast genes. By using mutants deficient in each of the two major yeast CO-binding hemoproteins (cytochrome c oxidase and flavohemoglobin), respiratory inhibitors, and cob1 and rho0 mutants, we have found that the respiratory chain is involved in the anoxic induction of these two genes and that cytochrome c oxidase is likely the hemoprotein sensor. Our findings also indicate that there are at least two classes of hypoxic genes in yeast (CO sensitive and CO insensitive) and imply that multiple pathways/mechanisms are involved in modulating the expression of hypoxic yeast genes.
Kwast KE, Burke PV, Staahl BT, Poyton RO
Proceedings of the National Academy of Sciences of the United States of America
1999-05-11 00:00
96
10
5446-51
Aerobiosis,Antimycin A,Carbon Monoxide,Cobalt,Cytochrome c Group,Cytochromes c,Electron Transport Complex IV,Fatty Acid Desaturases,Gene Expression Regulation, Fungal,Genes, Fungal,Hemeproteins,Mutation,Nickel,Oxygen,Potassium Cyanide,RNA, Messenger,Saccharomyces cerevisiae,Cytochrome c Group,Hemeproteins,RNA, Messenger,iso-2-cytochrome C,Potassium Cyanide,Carbon Monoxide,Antimycin A,Nickel,Cobalt,Oxygen,Cytochromes c,Fatty Acid Desaturases,delta-9 fatty acid desaturase,Electron Transport Complex IV
Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA
Proc. Natl. Acad. Sci. U.S.A.
NIGMS GM30228
0027-8424
1057
True
10318903
