Poster Presentation 40th Annual Lorne Genome Conference 2019

Histone acetyltransferase p300 acetylates histone variant H2A.Z preferentially at H4 acetylated nucleosomes. (#130)

Yolanda Colino-Sanguino 1 , Evan Cornett 2 , David Moulder 1 , Scott Rothbart 2 , Susan J Clark 1 , Fatima Valdes-Mora 1
  1. Epigenetics Research/Genomics and Epigenetics Division, Garvan Institute of Medical Science, Darlinghurst, NSW, Australia
  2. Center of Epigenetics, Van Andel Research Institute, Grand Rapids, MI, USA

The compaction of chromatin is a highly dynamic process and regulates the access of cellular machinery to DNA. Chemical modifications of the histone tails and incorporation of histone variants act to modulate the chromatin structure. We have shown that acetylation of the histone variant H2A.Z (H2A.Zac) occurs at active regulatory regions and is associated with oncogenic activation in prostate cancer(Valdes-Mora et al., 2017; Valdes-Mora et al., 2012), however its specific histone acetyltransferase (HAT) is unknown. Previous studies have suggested that the Tip60 complex drives acetylation of H2A.Z however it remains elusive if the Tip60 HAT activity is able to acetylate H2A.Z directly (Bellucci et al., 2013; Dalvai et al., 2012). Here we show that H2A.Z is not acetylated by Tip60 HAT activity in vitro, but is acetylated by the mammal-specific HAT p300. We found that the transcriptional activator p300 acetylates H2A.Z at multiple lysines with a similar affinity to its well known substrate, H3K27. Chemical inhibition of p300 decreases H2A.Zac levels at the chromatin. In addition, we found that p300 bromodomain interaction with H4 acetylated histone tails, enhances p300 ability to acetylate H2A.Z in the nucleosome context. Moreover, ChIP-seq analysis of H2A.Zac and H4K5ac peaks show a high genomic overlap, especially at promoter regions where as acetylation at distal regulatory regions is more dynamic and both marks can be found alone or in combination. H2A.Zac and H4ac nucleosome occupancy at enhancers is differentially associated with the transcriptional activity of the expanded region. Together the data suggest that p300 mediated H2A.Z acetylation is H4ac and transcriptional context dependant. In conclusion, this study provides insights into the mechanism for H2AZ acetylation deposition and identifies p300 as a potential target for the modulation of this oncogenic mark in prostate cancer.

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  3. Valdes-Mora, F., Gould, C.M., Colino-Sanguino, Y., Qu, W., Song, J.Z., Taylor, K.M., Buske, F.A., Statham, A.L., Nair, S.S., Armstrong, N.J., et al. (2017). Acetylated histone variant H2A.Z is involved in the activation of neo-enhancers in prostate cancer. Nat Commun 8, 1346.
  4. Valdes-Mora, F., Song, J.Z., Statham, A.L., Strbenac, D., Robinson, M.D., Nair, S.S., Patterson, K.I., Tremethick, D.J., Stirzaker, C., and Clark, S.J. (2012). Acetylation of H2A.Z is a key epigenetic modification associated with gene deregulation and epigenetic remodeling in cancer. Genome Res 22, 307-321.