H3 Acetylation and H2A.Z Levels Interplay to Regulate Gene Expression and Plant Development

H2A.Z is a conserved histone variant that plays essential roles in various DNA-templated processes across eukaryotes. H2A.Z and histone post-translational modifications (PTMs) exert a bidirectional and context-dependent influence on each other. Nevertheless, the functions of the interplay between PTMs and H2A.Z level and the underlying molecular mechanism remain poorly understood. Here, we found that the loss of the histone acetyltransferase GCN5 impedes the overexpression of BSU1 typically observed in nrp1-1 nrp2-2, accompanied by changes in H3 acetylation and H2A.Z levels. Interestingly, the increment in H2A.Z levels typical of nrp1-1 nrp2-2 mutant alleviates the morphological and molecular phenotypes of gcn5. Conversely, H2A.Z-depleted mutants aggravate the phenotype of gcn5. In the gcn5 mutant, the H2A.Z level is globally reduced in the gene bodies, and this reduction is dependent on the histone chaperones NRP1 and NRP2. Additionally, the reduction of H3 acetylation levels caused by GCN5 depletion can be recovered in the nrp1-1 nrp2-2 mutant background, likely due to the over-accumulation of H2A.Z. In conclusion, our genetic, molecular, and genomic findings demonstrate that GCN5-mediated H3 acetylation promotes H2A.Z deposition, H2A.Z over-accumulation recovers the loss of GCN5-mediated H3 acetylation, and this interplay is crucial for regulating gene expression and plant development. ChIP-seq of H3 acetylation and histone H2A.Z in Columbia (WT) and gcn5-7, nrp1-1 nrp2-2, gcn5-7 nrp1-1 nrp2-2 backgrounds.The experimental tissues were collected form 12 day after germination (12DAG) from seedlings cultured on GM medium (1x MS salts, 1% sucrose, pH=5.7).