Description
Histone tail modificationscan greatly influencechromatin-associated processes. Asymmetrically modified nucleosomes exist inmultiple cell types; however,whether modifications on both sister histones contribute equally to chromatin dynamicsremainselusive. Here, we devised a bivalent nucleosome system thatallowedfor the constitutive assembly of asymmetrically modified sister histone H3s in nucleosomes inSaccharomyces cerevisiae. The sister H3K36 methylationsaffectedcryptic transcription in gene coding regions, whereassister H3K79 methylation had cooperative effectsongene silencing near telomeres.H3K4 methylation on sister histonesplayed an independent role in suppressing the recruitmentof the Gal4 activator and inhibitingGAL1transcription. Under starvation stress, the expression of glycometabolism pathway geneswasfinetuned by sisterH3K4 methylation.Thus,different modifications on sister histones act either cooperatively or independentlyto regulate transcription in response to external stimuli. Overall design: Examination of the profile of RNA transcription of different mutants under glucose starvation (0.05% glucose)