Arabidopsis SUMO E3 Ligase SIZ1 Interacts with HDA6 and Negatively Regulates HDA6 Function during Flowering.

Sujuan Gao,Yishui Huang,Xueqin Zeng,Keqiang Wu,Jianhao Wang,Yingchao Xu,Feng Wang,Songguang Yang,Chunwei Yu

doi:10.3390/cells10113001

Abstract

The changes in histone acetylation mediated by histone deacetylases (HDAC) play a crucial role in plant development and response to environmental changes. Mammalian HDACs are regulated by post-translational modifications (PTM), such as phosphorylation, acetylation, ubiquitination and small ubiquitin-like modifier (SUMO) modification (SUMOylation), which affect enzymatic activity and transcriptional repression. Whether PTMs of plant HDACs alter their functions are largely unknown. In this study, we demonstrated that the Arabidopsis SUMO E3 ligase SAP AND MIZ1 DOMAIN-CONTAINING LIGASE1 (SIZ1) interacts with HISTONE DEACETYLASE 6 (HDA6) both in vitro and in vivo. Biochemical analyses indicated that HDA6 is not modified by SUMO1. Overexpression of HDA6 in siz1-3 background results in a decreased level of histone H3 acetylation, indicating that the activity of HDA6 is increased in siz1-3 plants. Chromatin immunoprecipitation (ChIP) assays showed that SIZ1 represses HDA6 binding to its target genes FLOWERING LOCUS C (FLC) and MADS AFFECTING FLOWERING 4 (MAF4), resulting in the upregulation of FLC and MAF4 by increasing the level of histone H3 acetylation. Together, these findings indicate that the Arabidopsis SUMO E3 ligase SIZ1 interacts with HDA6 and negatively regulates HDA6 function.

Highlights

IntroductionHistone proteins have a structured globular domain and an unstructured amino-terminal tail that protrudes from the core nucleosome
In eukaryotes, each nucleosome consists of 147 bp of DNA wrapped twice around a cylindrical protein core containing two copies of each histone: H2A, H2B, H3, and H4 [1,2].Histone proteins have a structured globular domain and an unstructured amino-terminal tail that protrudes from the core nucleosome
Previous proteomic data demonstrated that HDA19 conjugates with SUMO1/SUMO2 mediated by SAP AND MIZ1 DOMAIN-CONTAINING LIGASE1 (SIZ1) [46,47]

Summary

Introduction

Histone proteins have a structured globular domain and an unstructured amino-terminal tail that protrudes from the core nucleosome. These histone tails can be altered through a variety of post-translational modifications (PTM) including acetylation, phosphorylation, methylation, ubiquitination, and ADP-ribosylation [3]. All these PTMs are reversible, and their dynamics are controlled by two classes of histone-modifying enzymes with opposing effects of addition and removal. Based on the sequence homology and substrate specificity, HDACs are grouped into three major classes in plants: REDUCED POTASSIUM DEPENDENCE 3/HISTONE DEACETYLASE 1

Methods

Results

Conclusion