LHP1 Regulates H3K27me3 Spreading and Shapes the Three-Dimensional Conformation of the Arabidopsis Genome.

Alaguraj Veluchamy,Cécile Raynaud,Kiruthiga Gayathri Mariappan,Moussa Benhamed,Soon-Kap Kim,Federico Ariel,Heribert Hirt,Martin Crespi,Catherine Bergounioux,David Latrasse,Teddy Jégu

doi:10.1371/journal.pone.0158936

Abstract

Precise expression patterns of genes in time and space are essential for proper development of multicellular organisms. Dynamic chromatin conformation and spatial organization of the genome constitute a major step in this regulation to modulate developmental outputs. Polycomb repressive complexes (PRCs) mediate stable or flexible gene repression in response to internal and environmental cues. In Arabidopsis thaliana, LHP1 co-localizes with H3K27me3 epigenetic marks throughout the genome and interacts with PRC1 and PRC2 members as well as with a long noncoding RNA. Here, we show that LHP1 is responsible for the spreading of H3K27me3 towards the 3’ end of the gene body. We also identified a subset of LHP1-activated genes and demonstrated that LHP1 shapes local chromatin topology in order to control transcriptional co-regulation. Our work reveals a general role of LHP1 from local to higher conformation levels of chromatin configuration to determine its accessibility to define gene expression patterns.

Highlights

During development of multicellular organisms, early embryonic cells must adopt particular gene expression patterns to differentiate into a variety of functionally specialized cells in tissues and organs [1]
Previous studies based on ChiP-chip [33] and tilling arrays [34] showed that LHP1 occupancy correlates with the H3K27me3 repressive mark predominantly in euchromatic regions of the Arabidopsis genome
When we assessed the distribution of LHP1 along the genes and their flanking regions, we observed a significant enrichment across the gene body, along with H3K27me3 (Fig 1D)

Summary

Introduction

During development of multicellular organisms, early embryonic cells must adopt particular gene expression patterns to differentiate into a variety of functionally specialized cells in tissues and organs [1]. Eukaryotic DNA is wrapped in the nucleus around histone octamers into nucleosomes conforming chromatin structure in association to other proteins and RNA. Covalent modifications of DNA and histones may recruit protein complexes to remodel chromatin, altering its compaction and shaping the three-dimensional topology of the genome. Chromatin structure and genome topology are sensitive to regulatory cues and determine the accessibility of DNA to transcription factors in order to dynamically modulate gene transcription and other genome functions [2].

Methods

Results

Conclusion