Histone H3 serine 57 and lysine 56 interplay in transcription elongation and recovery from S-phase stress.
BACKGROUND
Acetylation of lysine 56 of histone H3 plays an important role in the DNA damage response and it has been postulated to play an as yet undefined role in transcription, both in yeast and in higher eukaryotes. Because phosphorylated human histone H3 serine 57 peptides have been detected by mass spectrometry we examined whether H3-S57 phosphorylation interplays with H3-K56 acetylation in vivo.


RESULTS
To explore the physiological role of H3-S57, H3-K56 was mutated to mimic constitutively (un)acetylated forms of H3-K56 and these were combined with constitutively (un)phosphorylated mimics of H3-S57, in yeast. A phosphorylated serine mimic at position 57 lessened sensitivities to a DNA replication fork inhibitor and to a transcription elongation inhibitor that were caused by an acetylated lysine mimic at position 56, while the same substitution exacerbated sensitivities due to mimicking a constitutive non-acetylated lysine at position 56. Strikingly, opposite results were obtained in the context of a serine to alanine substitution at position 57 of histone H3.


CONCLUSIONS
The phenotypes elicited and the context-dependent interplay of the H3-K56 and -S57 point mutations that mimic their respective modification states suggest that serine 57 phosphorylation promotes a nucleosomal transaction when lysine 56 is acetylated. We speculate that histone H3-S57 couples H3-K56 acetylation to histone quaternary structures involving arginine 40 on histone H4 helix 1.
Department of Molecular Biology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen, The Netherlands.
Aamir
A
Aslam
Colin
C
Logie
D019943:Amino Acid Substitution / Q000235:genetics; D002999:Clone Cells; D004249:DNA Damage; D016195:G2 Phase / Q000187:drug effects; D005799:Genes, Dominant / Q000235:genetics; D006367:HeLa Cells; D006657:Histones / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008239:Lysine / Q000378:metabolism*; D008741:Methyl Methanesulfonate / Q000633:toxicity; D008938:Mitosis / Q000187:drug effects; D009154:Mutation / Q000235:genetics; D010766:Phosphorylation / Q000187:drug effects; D016196:S Phase / Q000187:drug effects / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D012694:Serine / Q000378:metabolism*; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics*; D013489:Suppression, Genetic / Q000187:drug effects; D014158:Transcription, Genetic / Q000187:drug effects
D006657:Histones; D012694:Serine; D008741:Methyl Methanesulfonate; D008239:Lysine