CPF1, a yeast protein which functions in centromeres and promoters

Abstract

Centromeres and several promoters of Saccharomyces cerevisiae contain a highly conserved octanucleotide, RTCACRTG, called CDEI. Using biochemical, genetic and structural analyses, we show that the same protein binds in vivo to CDEI sites in centromeres and in promoters. This protein, called CPF1 for centromere promoter factor, binds DNA as a dimer. Inactivation of the gene is not lethal but leads to a partial loss of the centromere function and to a Met- phenotype. Changes of the chromatin structure due to inactivation of CPF1 are seen at centromeres and at several CDEI-carrying promoters (e.g. MET25, TRP1, GAL2). However promoter activities are affected in diverse ways making it presently difficult to describe a function for CPF1 in gene expression. The sequence of the cloned gene reveals in the carboxy-terminal part two potential amphipathic helices preceded by a positively charged stretch of amino acids very similar to the helix-loop-helix domains recently identified in factors controlling tissue specific transcription in higher eukaryotes. Carboxy-terminal truncations of CPF1 lacking this domain no longer bind to CDEI. The amino-terminal half of CPF1 carries two clusters of negatively charged amino acid residues. Surprisingly, deletions of these clusters still render cells Met+ and lead only to a marginal decrease in centromere activity.