Document Detail


Characterization of a positive regulatory gene, LAC9, that controls induction of the lactose-galactose regulon of Kluyveromyces lactis: structural and functional relationships to GAL4 of Saccharomyces cerevisiae.
MedLine Citation:
PMID:  3550430     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Lactose or galactose induces the expression of the lactose-galactose regulon in Kluyveromyces lactis. We show here that the regulon is not induced in strains defective in LAC9. We demonstrate that this gene codes for a regulatory protein that acts in a positive manner to induce transcription. The LAC9 gene was isolated by complementation of a lac9 defective strain. DNA sequence analysis of the gene gave a deduced protein of 865 amino acids. Comparison of this sequence with that of the GAL4 protein of Saccharomyces cerevisiae revealed three regions of homology. One region of about 90 amino acid occurs at the amino terminus, which is known to mediate binding of GAL4 protein to upstream activator sequences. We speculate that a portion of this region, adjacent to the "metal-binding finger," specifies DNA binding. We discuss possible functions of the two other regions of homology. The functional implications of these structural similarities were examined. When LAC9 was introduced into a gal4 defective strain of S. cerevisiae it complemented the mutation and activated the galactose-melibiose regulon. However, LAC9 did not simply mimic GAL4. Unlike normal S. cerevisiae carrying GAL4, the strain carrying LAC9 gave constitutive expression of GAL1 and MEL1, two genes in the regulon. The strain did show glucose repression of the regulon, but repression was less severe with LAC9 than with GAL4. We discuss the implications of these results and how they may facilitate our understanding of the LAC9 and GAL4 regulatory proteins.
Authors:
L V Wray; M M Witte; R C Dickson; M I Riley
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Molecular and cellular biology     Volume:  7     ISSN:  0270-7306     ISO Abbreviation:  Mol. Cell. Biol.     Publication Date:  1987 Mar 
Date Detail:
Created Date:  1987-05-18     Completed Date:  1987-05-18     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  8109087     Medline TA:  Mol Cell Biol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1111-21     Citation Subset:  IM    
Data Bank Information
Bank Name/Acc. No.:
GENBANK/M15210
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MeSH Terms
Descriptor/Qualifier:
Base Sequence
Chromosome Mapping
DNA, Fungal / genetics
Galactose / genetics
Genes, Fungal*
Genes, Regulator*
Genetic Complementation Test
Kluyveromyces / genetics*
Lactose / genetics
Mutation
Saccharomyces cerevisiae / genetics*
Saccharomycetales / genetics*
Transcription, Genetic
Grant Support
ID/Acronym/Agency:
1U41RR-01685-02/RR/NCRR NIH HHS; GM-22749/GM/NIGMS NIH HHS
Chemical
Reg. No./Substance:
0/DNA, Fungal; 26566-61-0/Galactose; 63-42-3/Lactose
Comments/Corrections

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