Yeast X‐chromosome‐associated protein 5 (Xap5) functions with H2A.Z to suppress aberrant transcripts

Chromatin regulatory proteins affect diverse developmental and environmental response pathways via their influence on nuclear processes such as the regulation of gene expression. Through a genome‐wide genetic screen, we implicate a novel protein called X‐chromosome‐associated protein 5 (Xap5) in chromatin regulation. We show that Xap5 is a chromatin‐associated protein acting in a similar manner as the histone variant H 2 A . Z to suppress expression of antisense and repeat element transcripts throughout the fission yeast genome. Xap5 is highly conserved across eukaryotes, and a plant homolog rescues xap5 mutant yeast. We propose that X ap5 likely functions as a chromatin regulator in diverse organisms.