Replacement of Arabidopsis H2A.Z with human H2A.Z orthologs reveals extensive functional conservation and limited importance of the N-terminal tail sequence for Arabidopsis development

• Type of Material: Article
• Authors: Paja Sijacic, Emory University; Dylan Holder, Emory University; Ellen Krall, Emory University; Courtney G. Willett, Emory University; Maryam Foroozani, Emory University; Roger Deal, Emory University
• Language: English
• Date: 2024-07-12
• Publisher: NIH
• Publication Version: Preprint (Prior to Peer Review)
• Copyright Statement: The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): https://doi.org/10.1101/2023.11.03.565555
• Title of Journal or Parent Work: bioRxiv
• Start Page: 565555
• Grant/Funding Information: This work was supported by funding from the National Institutes of Health (R01GM134245) to RBD. DHH and EGK were also supported by an NIH training grant (T32GM008490).
• Keywords: transcription; nucleosome; chromatin; H2A.Z; Histone variant
• Research Categories: Biology, Genetics; Biology, Molecular

Abstract

The incorporation of histone variants, distinct paralogs of core histones, into chromatin affects all DNA-templated processes in the cell, including the regulation of transcription. In recent years, much research has been focused on H2A.Z, an evolutionarily conserved H2A variant found in all eukaryotes. In order to investigate the functional conservation of H2A.Z histones during eukaryotic evolution we transformed h2a.z deficient plants with each of the three human H2A.Z variants to assess their ability to rescue the mutant defects. We discovered that human H2A.Z.1 and H2A.Z.2.1 fully complement the phenotypic abnormalities of h2a.z plants despite significant divergence in the N-terminal tail sequences of Arabidopsis and human H2A.Zs. In contrast, the brain-specific splice variant H2A.Z.2.2 has a dominant-negative effect in wild-type plants, mimicking an H2A.Z deficiency phenotype. Furthermore, H2A.Z.1 almost completely re-establishes normal H2A.Z chromatin occupancy in h2a.z plants and restores the expression of more than 84% of misexpressed genes. Finally, we used a series of N-terminal tail truncations of Arabidopsis HTA11 to reveal that the N-terminal tail of Arabidopsis H2A.Z is not necessary for normal plant development but does play an important role in mounting proper environmental stress responses.