ISSN:
1432-0983
Keywords:
Key wordsMAL-activator
;
Constitutive mutations
;
Maltose fermentation
;
Saccharomyces
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The Saccharomyces MAL-activator regulates the maltose-inducible expression of the MAL structural genes encoding maltose permease and maltase. Constitutive MAL-activator mutant alleles of two types were identified. The first were truncation mutations deleting C-terminal residues 283–470 and the second contained a large number of alterations compared to inducible alleles scattered throughout the C-terminal 200 residues. We used site-directed in vitro mutagenesis of the inducible MAL63 and MAL63/23 genes to identify the residues responsible for the negative regulatory function of the C-terminal domain. Intragenic suppressors that restored the inducible phenotype to the constitutive mutants were identified at closely linked and more distant sites within the MAL-activator protein. MAL63/mal64 fusions of the truncated mutants suggest that residues in the N-terminal 100 residues containing the DNA-binding domain also modulate basal expression. Moreover, a transcription activator protein consisting of LexA(1–87)-Gal4(768–881)-Mal63(200–470) allowed constitutive reporter gene expression, suggesting that the C-terminal regulatory domain is not sufficient for maltose-inducible control of this heterologous activation domain. These results suggest that complex and very specific intramolecular protein–protein interactions regulate the MAL-activator.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002940000161
Permalink
