Epigenetic reprogramming by histone acetyltransferase HAG1/AtGCN5 is required for pluripotency acquisition in Arabidopsis

Abstract

Shoot regeneration can be achieved through a two-step process involving the acquisition of pluripotency on callus-induction media (CIM) and the formation of shoots on shoot-induction media. Although the induction of root-meristem genes in callus has been noted recently, the mechanisms underlying their induction and their roles in shoot regeneration remain unanswered. Here, we show that the histone acetyltransferase HAG1/AtGCN5 is essential for shoot regeneration. In developing callus, it catalyzes histone acetylation at several root-meristem gene loci including, ,, , and, providing an epigenetic platform for their transcriptional activation. In turn, we demonstrate that the transcription factors encoded by these loci act as key potency factors conferring regeneration potential to callus and establishing competence for shoot regeneration. Thus, our study uncovers key epigenetic and potency factors regulating plant-cell pluripotency. These factors might be useful in reprogramming lineage-specified plant cells to pluripotency.

Histone acetylation orchestrates wound-induced transcriptional activation and cellular reprogramming in Arabidopsis

“…Interestingly, histone acetylation promotes wound-induced callus formation ( Fig. 6) but inhibits hormone-induced callus formation under in vitro conditions 50 . Thus, it appears that histone acetylation is not generally associated with onset of cell proliferation and callus formation, and that it is instead required for specific upstream processes during wound-induced callus formation.…”

“…6). A recent study, showed that HAG1/GCN5-dependent histone acetylation is necessary for in vitro shoot regeneration 50 , by acetylating histones of several key root meristem genes, thereby activating their expression in hormone-induced callus. Our study thus together demonstrates a role for GNAT-MYST-mediated histone acetylation in both wound-and hormone-induced regeneration.…”

“…In Arabidopsis, four histone acetyltransferases subfamilies exists, GCN5-related N-terminal acetyltransferases (GNATs), MYST (MOZ, Ybf2/Sas3, Sas2 and Tip60)-related, p300/CREB-binding protein (CBP)related, and transcription initiation factors TAF II 250-related 48 . Importantly, inhibition of HISTONE ACETYLTRANSFERASE OF THE GNAT/MYST SUPERFAMILY 1/GENERAL CON-TROL NONREPRESSED 5 (HAG1/GCN5) or histone deacetylases interferes with hormone-induced callus formation and shoot regeneration in vitro 49,50 , suggesting that histone acetylation is essential for transcriptional reprogramming during hormoneinduced regeneration.…”

Genome-Wide Identification of Histone Acetyltransferases and Deacetylases in Epiphytic Orchid Plant Dendrobium Catenatum

“…Arabidopsis GCN5 is implicated in regulating PLETHORA (PLT) gradient-mediated root stem cell niche maintenance and transit amplifying cell proliferation [21]. AtHAG1/GCN5 is involved in establishment of competence for de novo shoot regeneration through acting as an epigenetic switch that renders somatic cells to acquire regeneration potential via catalyzing histone acetylation at key root-meristem gene loci in developing callus [22].…”

Epigenetically jump starting de novo shoot regeneration

“…This study by Kim et al (2018) not only offers significant novel insight into the mechanism of in vitro regeneration, but also provides entry points for important future studies. What are the first steps after treating explants with a high auxin/cytokinin hormone regime that eventually result in WOX and SCR gene upregulation?…”