BMB reports

The eukaryotic genome forms a chromatin structure that con-tains repeating nucleosome structures. Nucleosome packaging is regulated by chromatin remodeling factors such as histone chaperones. The Saccharomyces cerevisiae H3/H4 histone chaperones, CAF-1 and Asf1, regulate DNA replication and chromatin assembly. CAF-1 function is largely restricted to non-transcriptional processes in heterochromatin, whereas Asf1 regulates transcription together with another H3/H4 chaperone, HIR. This study examined the role of the yeast H3/H4 histone chaperones, Asf1, HIR, and CAF-1 in chromatin dynamics dur-ing transcription. Unexpectedly, CAF-1 was recruited to the ac-tively transcribed region in a similar way to HIR and Asf1. In ad-dition, the three histone chaperones genetically interacted with Set2-dependent H3 K36 methylation. Similar to histone chaper-ones, Set2 was required for tolerance to excess histone H3 but not to excess H2A, suggesting that CAF-1, Asf1, HIR, and Set2 function in a related pathway and target chromatin during transcription. [BMB reports 2009; 42(4): 227-231