Encoded within the yeast genome are two sets of genes that are regulated in opposite fashion by heme, a cellular gauge of oxygen availability. One set is comprised of mitochondrial-functioning genes that are activated in the presence of heme, and the other set is comprised of genes believed to also serve some mitochondrial role tat are repressed in the presence of heme. In addition to sharing heme as the signal for oxygen, these two sets of genes share common regulatory factors. It is the goal of this study to define the components involved in the regulation of these genes and determine how the coordinate regulation is achieved. This study will focus on the CYC7 gene which encodes iso-2- cytochrome c, the minor cytochrome c species of the cell. This gene has the unusual property of possessing regulatory signals that respond both positively and negatively to heme, thereby sharing regulatory components with the two sets of oppositely regulated genes. The basepairs that comprise the cis-acting regulatory sequences of this gene will be defined in detail using the techniques of in vitro mutagenesis. The effect of the different regulatory sequences transplanted into an unrelated gene will be studied so that their individual contribution to the overall regulation of CYC7 can be assessed. Three trans-acting regulatory genes, the ROX genes, have been identified that are involved in the regulation of CYC7 and other heme regulated genes. These genes will be cloned by complementation of their mutant phenotypes, and their gene products will be identified. These gene products will be assessed for specific DNA binding activity and the ability to form complexes with other DNA binding proteins. Selection schemes for the isolation of additional regulatory mutations are proposed. Two other genes, the CYC1 gene which is positively regulated by heme, and the ANB1 gene which is negatively regulated by heme will be used as markers for the two sets of heme regulated genes. The effect of trans-acting factors which regulate CYC7 will be tested on these genes, and sequences which are found to serve as regulatory sites in CYC7 will be sought in these genes.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
2R01GM026061-08
Application #
3273526
Study Section
Genetics Study Section (GEN)
Project Start
1978-12-01
Project End
1992-08-31
Budget Start
1987-09-01
Budget End
1988-08-31
Support Year
8
Fiscal Year
1987
Total Cost
Indirect Cost
Name
State University of New York at Albany
Department
Type
Schools of Arts and Sciences
DUNS #
City
Albany
State
NY
Country
United States
Zip Code
12222
Bose, Sohini; Dutko, James A; Zitomer, Richard S (2005) Genetic factors that regulate the attenuation of the general stress response of yeast. Genetics 169:1215-26
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Mennella, Thomas A; Klinkenberg, Lee G; Zitomer, Richard S (2003) Recruitment of Tup1-Ssn6 by yeast hypoxic genes and chromatin-independent exclusion of TATA binding protein. Eukaryot Cell 2:1288-303
Khalaf, R A; Zitomer, R S (2001) The DNA binding protein Rfg1 is a repressor of filamentation in Candida albicans. Genetics 157:1503-12
Limbach, M P; Zitomer, R S (2000) The isolation and characterization of missense mutants in the general repressor protein Ssn6 of Saccharomyces cerevisiae. Mol Gen Genet 263:455-62
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Deckert, J; Khalaf, R A; Hwang, S M et al. (1999) Characterization of the DNA binding and bending HMG domain of the yeast hypoxic repressor Rox1. Nucleic Acids Res 27:3518-26
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Zitomer, R S; Limbach, M P; Rodriguez-Torres, A M et al. (1997) Approaches to the study of Rox1 repression of the hypoxic genes in the yeast Saccharomyces cerevisiae. Methods 11:279-88

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