Distinct development-associated roles of rice histone variant H2A.X in suppressing deposition of active H3K4me3 marks and in restricting H2A.W incorporation [RNA-Seq]

Although H2A.X expresses even without any stress, and decorates gene bodies of actively expressed genes, it is not known if H2A.X has functions beyond DNA damage repair. Using genetic, high throughput genomics and molecular approaches, we identified a previously unappreciated role of H2A.X in regulating development-associated genes.

H2A.X suppressed the deposition of active H3K4me3 marks over gene bodies and Transposable elements (TE)s, specifically regulating several root development, photosynthesis, and pigmentation-related genes as seen by the impairment of these processes in h2a.x ko plants. H2A.X also suppressed global deposition of H3K9me2 repressive mark by restricting activity of H2A variant H2A.W. In agreement with this, there was a genome-wide re-localization of H2A.W to TEs and a few genes in h2a.x ko plants.