Mutational analysis of the Saccharomyces cerevisiae general regulatory factor CP1.
The Saccharomyces cerevisiae general regulatory factor CP1, a helix-loop-helix protein that binds the centromere DNA element I (CDEI) of yeast centromeres, is required in yeast for optimal centromere function and for methionine prototrophy. Mutant alleles of CEP1, the gene encoding CP1, were generated by linker insertion, 5'- and 3'-deletion, and random mutagenesis and assayed for DNA binding activity and their ability to confer CP1 function when expressed in yeast. A heterologous CDEI-binding protein, TFEB, was also tested for CP1 function. The results suggested that DNA binding is required for both biological functions of CP1 but is not sufficient. A direct and quantitative correlation was observed between the chromosome loss and nutritional (i.e., Met) phenotypes of strains carrying loss of function alleles, but qualitatively the chromosome loss phenotype was more sensitive to decreased CP1 expression. The data are consistent with a model in which CP1 performs the same general chromatin-related function at centromeres and MET gene promoters and is normally present in functional excess.
Masison
D C
DC
Department of Molecular Genetics and Microbiology, University of Massachusetts Medical School, Worcester 01655.
O'Connell
K F
KF
Baker
R E
RE
D000483:Alleles; D001483:Base Sequence; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D004252:DNA Mutational Analysis; D004271:DNA, Fungal; D004268:DNA-Binding Proteins / Q000235:genetics*; D016368:Frameshift Mutation; D005656:Fungal Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010641:Phenotype; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D014170:Transformation, Genetic
D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; C064042:CBF1 protein, S cerevisiae; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins