Putative Arabidopsis Transcriptional Adaptor Protein (PROPORZ1) is required to modulate histone acetylation in response to auxin

Abstract

Plant development is highly adaptable and controlled by a combination of various regulatory circuits that integrate internal and environmental cues. The phytohormone auxin mediates such growth responses, acting as a dynamic signal in the control of morphogenesis via coordinating the interplay between cell cycle progression and cell differentiation. Mutants in the chromatin-remodeling component PROPORZ1 (PRZ1; also known as AtADA2b) are impaired in auxin effects on morphogenesis, suggestive of an involvement of PRZ1-dependent control of chromatin architecture in the determination of hormone responses. Here we demonstrate that PRZ1 is required for accurate histone acetylation at auxin-controlled loci. Specifically, PRZ1 is involved in the modulation of histone modifications and corresponding adjustments in gene expression of Arabidopsis KIP RELATED PROTEIN ( KRP ) CDK inhibitor genes in response to auxin. Deregulated KRP expression in KRP silencer lines phenocopies prz1 hyperproliferative growth phenotypes, whereas in a KRP overexpression background some mutant phenotypes are suppressed. Collectively, our findings support a model in which translation of positional signals into developmental cues involves adjustments in chromatin modifications that orchestrate auxin effects on cell proliferation.

A Genome-Wide Chronological Study of Gene Expression and Two Histone Modifications, H3K4me3 and H3K9ac, during Developmental Leaf Senescence

“…The high coincidence of H3K4me3 and H3K9ac marks (Fig. 2) has been noted previously (Kim et al, 2008(Kim et al, , 2010(Kim et al, , 2012Anzola et al, 2010;Roudier et al, 2011;Malapeira et al, 2012) and supports the validity of the H3K9ac data sets. Although the coincidence of these two modifications has been noted before, our observation that the extent of H3K9ac coverage per gene was about 60% of the H3K4me3 coverage level is unique.…”

“…2C). A cooperative interaction between H3K4me3 and H3K9ac modifications is suggested by the high degree of colocalization, which has been noted previously (Kim et al, 2008(Kim et al, , 2012Anzola et al, 2010;Jaskiewicz et al, 2011;Roudier et al, 2011;Malapeira et al, 2012).…”

“…The abundance of H3K4me3 and H3K9ac histone modifications changes at specific loci during numerous developmental transitions in plants (Kim et al, 2008(Kim et al, , 2009a(Kim et al, , 2012Charron et al, 2009;Adrian et al, 2010;Anzola et al, 2010;van Dijk et al, 2010;Brusslan et al, 2012;Malapeira et al, 2012;López-González et al, 2014;Molitor et al, 2014;Schenke et al, 2014), and thus, it is likely that the final stage of leaf development, leaf senescence, would be accompanied by changes in these two well-characterized histone modifications that positively correlate with gene expression. Leaves were harvested from progressively more senescent plants and subject to RNA-seq and ChIP-seq, so that a direct correlation between gene expression and Table II.…”

The Arabidopsis transcription factor bZIP11 activates auxin-mediated transcription by recruiting the histone acetylation machinery

“…As members of the GH3, IAA and PIN gene families are regulated in a similar manner, we assume a more general impact of histone acetylation on auxin-mediated gene expression. In fact, recently published results highlight the relevance of ADA2b and GCN5 on auxin-regulated transcription 24,25 .…”

“…In fact, gcn5 and ada2b mutants, in which SAGA complex formation should be disrupted, exhibit several abnormal auxin-related growth phenotypes 20,[22][23][24] . Moreover, GCN5 has been found in a mutant suppressor screen for the corepressor TPL 24 and ADA2b was shown to be required for histone acetylation in response to auxin 25 . Consistently, the ada2b-mutant plants are impaired in translating auxin signals into proper morphogenetic responses 26 .…”