AtEAF1 is a potential platform protein for Arabidopsis NuA4 acetyltransferase complex

Abstract

BackgroundHistone acetyltransferase complex NuA4 and histone variant exchanging complex SWR1 are two chromatin modifying complexes which act cooperatively in yeast and share some intriguing structural similarities. Protein subunits of NuA4 and SWR1-C are highly conserved across eukaryotes, but form different multiprotein arrangements. For example, the human TIP60-p400 complex consists of homologues of both yeast NuA4 and SWR1-C subunits, combining subunits necessary for histone acetylation and histone variant exchange. It is currently not known what protein complexes are formed by the plant homologues of NuA4 and SWR1-C subunits.ResultsWe report on the identification and molecular characterization of AtEAF1, a new subunit of Arabidopsis NuA4 complex which shows many similarities to the platform protein of the yeast NuA4 complex. AtEAF1 copurifies with Arabidopsis homologues of NuA4 and SWR1-C subunits ARP4 and SWC4 and interacts physically with AtYAF9A and AtYAF9B, homologues of the YAF9 subunit. Plants carrying a T-DNA insertion in one of the genes encoding AtEAF1 showed decreased FLC expression and early flowering, similarly to Atyaf9 mutants. Chromatin immunoprecipitation analyses of the single mutant Ateaf1b-2 and artificial miRNA knock-down Ateaf1 lines showed decreased levels of H4K5 acetylation in the promoter regions of major flowering regulator genes, further supporting the role of AtEAF1 as a subunit of the plant NuA4 complex.ConclusionsGrowing evidence suggests that the molecular functions of the NuA4 and SWR1 complexes are conserved in plants and contribute significantly to plant development and physiology. Our work provides evidence for the existence of a yeast-like EAF1 platform protein in A. thaliana, filling an important gap in the knowledge about the subunit organization of the plant NuA4 complex.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-015-0461-1) contains supplementary material, which is available to authorized users.

Arabidopsis YAF9 histone readers modulate flowering time through NuA4‐complex‐dependent H4 and H2A.Z histone acetylation at FLC chromatin

“…Phylogenetic analysis showed that both proteins are homologues to yeast Yaf9 ( Fig. S1a) and were designated as YAF9A and YAF9B, respectively (Zacharaki et al, 2012;Bieluszewski et al, 2015). The deduced YAF9A and YAF9B polypeptides have predicted molecular weights c. 30 kDa and share 56% amino acid sequence identity ( Fig.…”

Dual Role of the Histone Variant H2A.Z in Transcriptional Regulation of Stress-Response Genes

“…This may suggest that in the absence of a functional SWR1 complex, other mechanisms can occasionally incorporate H2A.Z into chromatin (ColemanDerr and Zilberman, 2012;Hardy et al, 2009). However, as no other biological function of SWR1 has been identified, both arp6 and pie1 mutants have been widely used to study the effects of H2A.Z depletion from chromatin (Choi et al, 2013;Kumar and Wigge, 2010;Smith et al, 2010;Bieluszewski et al, 2015;Zilberman et al, 2008;Rosa et al, 2013).…”

The Composition of the Arabidopsis RNA Polymerase II Transcript Elongation Complex Reveals the Interplay between Elongation and mRNA Processing Factors

“…Surprisingly, apart from SPT16, no other TEFs and no RNAPII subunits were found to copurify with CDKC;2-GS. However, various subunits of the NuA4/SWR1 chromatin remodeling complex, with combined histone acetyl-transferase and chromatin remodeling activity (Bieluszewski et al, 2015) (Table 1), as well as several BRD4 (bromodomain-containing protein4)-like proteins (Supplemental Data Set 6) were detected in the CDKC;2-GS eluates. Since BRD4 proteins are involved in recruiting P-TEFb to chromatin containing acetylated histones at target genes in mammalian cells (Bisgrove et al, 2007;Jang et al, 2005), this mechanism may be conserved in plants.…”