The long range goal of this project is to identify and characterize molecular mechanisms regulating gene expression in eukaryotes. Maltose fermentation in the Saccharomyces yeasts has been chosen as a model regulated system. The initial steps of maltose fermentation are carried out by maltose permease (the transport protein) and maltase (the cleavage enzyme). Synthesis of these enzymes is induced by maltose and repressed by glucose and both regulatory processes are controlled at the level of transcription. Our studies have identified a trans-acting positive factor, the MAL-activator protein, which mediates the transcriptional regulation of the structural genes encoding maltose permease and maltase. Maltose fermenting Saccharomyces strains contain at least one of a series of complex loci (MAL1, MAL2, MAL3, MAL4 and MAL6) each of which encodes maltose permease, maltase and the MAL-activator. The experiments described in this proposal are designed to reveal the details of the role played by the MAL-activator in regulating expression of the MAL structural genes. For this, we will a) complete our analysis of the functional domains of the MAL-activator using noninducible and constitutive mutations by in vitro and in vivo mutagenesis techniques; b) identify proteins which interact with the MAL-activator and play a role in maltose induction using the """"""""two hybrid protein system"""""""" and c) characterize the role of phosphorylation and/or proteolytic degradation of the MAL-activator in the regulation of fermentation. We will investigate the factors involved in regulating the synthesis of the MAL-activator itself by identifying upstream controlling elements of the MAL-activator gene. We will explore the role of MIG1 protein in the glucose repression of the MAL gene, both structural and regulatory. Finally, we plan to reinvestigate the reported position effect controlling the timed synthesis of maltase during the yeast cell cycle.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM028216-18
Application #
3275503
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Project Start
1980-07-01
Project End
1996-03-31
Budget Start
1993-04-01
Budget End
1994-03-31
Support Year
18
Fiscal Year
1993
Total Cost
Indirect Cost
Name
Queens College
Department
Type
Schools of Arts and Sciences
DUNS #
City
Flushing
State
NY
Country
United States
Zip Code
11367
Ran, Fulai; Gadura, Nidhi; Michels, Corinne A (2010) Hsp90 cochaperone Aha1 is a negative regulator of the Saccharomyces MAL activator and acts early in the chaperone activation pathway. J Biol Chem 285:13850-62
Ran, Fulai; Bali, Mehtap; Michels, Corinne A (2008) Hsp90/Hsp70 chaperone machine regulation of the Saccharomyces MAL-activator as determined in vivo using noninducible and constitutive mutant alleles. Genetics 179:331-43
Gadura, Nidhi; Michels, Corinne A (2006) Sequences in the N-terminal cytoplasmic domain of Saccharomyces cerevisiae maltose permease are required for vacuolar degradation but not glucose-induced internalization. Curr Genet 50:101-14
Gadura, Nidhi; Robinson, Lucy C; Michels, Corinne A (2006) Glc7-Reg1 phosphatase signals to Yck1,2 casein kinase 1 to regulate transport activity and glucose-induced inactivation of Saccharomyces maltose permease. Genetics 172:1427-39
Wang, Xin; Michels, Corinne A (2004) Mutations in SIN4 and RGR1 cause constitutive expression of MAL structural genes in Saccharomyces cerevisiae. Genetics 168:747-57
Bali, Mehtap; Zhang, Bin; Morano, Kevin A et al. (2003) The Hsp90 molecular chaperone complex regulates maltose induction and stability of the Saccharomyces MAL gene transcription activator Mal63p. J Biol Chem 278:47441-8
Danzi, Sara E; Bali, Mehtap; Michels, Corinne A (2003) Clustered-charge to alanine scanning mutagenesis of the Mal63 MAL-activator C-terminal regulatory domain. Curr Genet 44:173-83
Wang, Xin; Bali, Mehtap; Medintz, Igor et al. (2002) Intracellular maltose is sufficient to induce MAL gene expression in Saccharomyces cerevisiae. Eukaryot Cell 1:696-703
Jiang, H; Tatchell, K; Liu, S et al. (2000) Protein phosphatase type-1 regulatory subunits Reg1p and Reg2p act as signal transducers in the glucose-induced inactivation of maltose permease in Saccharomyces cerevisiae. Mol Gen Genet 263:411-22
Hu, Z; Yue, Y; Jiang, H et al. (2000) Analysis of the mechanism by which glucose inhibits maltose induction of MAL gene expression in Saccharomyces. Genetics 154:121-32

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