M. Adam et al., H2A.Z is required for global chromatin integrity and for recruitment of RNA polymerase II under specific conditions, MOL CELL B, 21(18), 2001, pp. 6270-6279
Evolutionarily conserved variant histone H2A.Z has been recently shown to r
egulate gene transcription in Saccharomyces cereviside. Here we show that l
oss of H2A.Z in this organism negatively affects the induction of GAL genes
. Importantly, fusion of the H2A.Z C-terminal region to S phase H2A without
its corresponding C-terminal region can mediate the variant histone's spec
ialized function in GAL1-10 gene induction, and it restores the slow-growth
phenotype of cells with a deletion of HTZ1. Furthermore, we show that the
C-terminal region of R2A.Z can interact with some components of the transcr
iptional apparatus. In cells lacking H2A.Z, recruitment of RNA polymerase I
I and TATA-binding protein to the GAL1-10 promoters is significantly dimini
shed under inducing conditions. Unexpectedly, we also find that H2A.Z is re
quired to globally maintain chromatin integrity under GAL gene-inducing con
ditions. We hypothesize that H2A.Z can positively regulate gene transcripti
on, at least in part, by modulating interactions with RNA polymerase II-ass
ociated factors at certain genes under specific cell growth conditions.