Histone Deacetylase HDA6 Is Functionally Associated with AS1 in Repression of KNOX Genes in Arabidopsis

Ming Luo,Yuhai Cui,Keqiang Wu,Linmao Zhao,Gang Tian,Jun-Yi Yang,Xuncheng Liu,Chun-Wei Yu,Fang-Fang Chen,Li-Jia Qu

doi:10.1371/journal.pgen.1003114

Abstract

ASYMMETRIC LEAVES 1 (AS1) is a MYB-type transcription repressor that controls leaf development by regulating KNOX gene expression, but the underlying molecular mechanism is still unclear. In this study, we demonstrated that AS1 can interact with the histone deacetylase HDA6 in vitro and in vivo. The KNOX genes were up-regulated and hyperacetylated in the hda6 mutant, axe1-5, indicating that HDA6 may regulate KNOX expression through histone deacetylation. Compared with the single mutants, the as1-1/axe1-5 and as2-1/axe1-5 double mutants displayed more severe serrated leaf and short petiole phenotypes. In addition, the frequencies of leaf lobes and leaflet-like structures were also increased in as1-1/axe1-5 and as2-1/axe1-5 double mutants, suggesting that HDA6 acts together with AS1 and AS2 in regulating leaf development. Chromatin immunoprecipitation assays revealed that HDA6 and AS1 bound directly to KNAT1, KNAT2, and KNATM chromatin. Taken together, these data indicate that HDA6 is a part of the AS1 repressor complex to regulate the KNOX expression in leaf development.

Highlights

The initiation of leaf primordia is established by recruitment of cells from the flanks of the shoot apical meristem (SAM)
We found that ASYMMETRIC LEAVES 1 (AS1) interacted with the histone deacetylase HDA6
Our data indicated that HDA6 is an important component of the AS1 repressor complex in regulating the KNOTTED-LIKE HOMOBOX (KNOX) gene expression

Summary

Introduction

The initiation of leaf primordia is established by recruitment of cells from the flanks of the shoot apical meristem (SAM). Meristem activity in the shoot apex is specified in part by the class I KNOTTED-LIKE HOMOBOX (KNOX) genes [1,2,3]. Lateral organs, such as leaves, are initiated on the flank of SAM, and downregulation of KNOX genes is essential to facilitate this process [1,4]. Class I KNOX genes are similar to KNOTTED1 (KN1) in maize, including BREVIPEDICELLUS (BP)/KNAT1, KNAT2, KNTA6 and SHOOTMERISTEMLESS (STM). These genes are expressed in the SAM and down-regulated in leaf primordia [8]. It was demonstrated that KNATM functions together with KNAT1 and BELL proteins by forming heterodimer [9]

Methods

Results

Discussion

Conclusion