Research News
Dr. Xin-Jian He’s laboratory reported that a plant-specific SWR1 chromatin remodeling complex couples histone H2A.Z deposition with nucleosome sliding
On March 2, 2020 ---- Dr. Xin-Jian He's laboratory published a research article titled “A plant-specific SWR1 chromatin remodeling complex couples histone H2A.Z deposition with nucleosome sliding” online in EMBO Journal. This study reported the identification of all components of the Arabidopsis SWR1 complex and revealed that the complex facilitates the coupling of H2A.Z and nucleosome sliding.
The
multi-subunit SWR1 complex is responsible for exchanging the H2A/H2B dimer of
the nucleosome with the free H2A.Z/H2B dimer, thereby depositing H2A.Z into the
chromatin in eukaryotes. Components of the SWR1 complexes have been well
identified and characterized in yeast and metazoans. Most of the conserved SWR1
components identified in yeast and metazoans have also been found in Arabidopsis,
suggesting that the SWR1 complexes are conserved in eukaryotes. However, it is
unknown whether there are non-conserved SWR1 components that are exclusively
present in plants. In this
study, Dr. Xin-Jian He’s laboratory identified all components of the SWR1
complex in Arabidopsis and found the following three classes of previously
uncharacterized plant-specific SWR1 components: MBD9, a methyl-CpG-binding
domain-containing protein; CHR11 and CHR17 (CHR11/17), ISWI chromatin
remodelers responsible for nucleosome sliding; and TRA1a and TRA1b, accessory
subunits of the conserved NuA4 histone acetyltransferase complex. MBD9 directly
interacts with CHR11/17 and the SWR1 catalytic subunit PIE1, and is responsible
for the association of CHR11/17 with the SWR1 complex. MBD9, TRA1a, and TRA1b
function as canonical components of the SWR1 complex to mediate H2A.Z
deposition. CHR11/17 are not only responsible for nucleosome sliding but are
also involved in H2A.Z deposition. The results indicate that the association of
the SWR1 complex with CHR11/17 may facilitate the coupling of H2A.Z deposition
with nucleosome sliding, thereby co-regulating gene expression, development,
and flowering time.
Figure 1. The protein-protein interaction as determined by IP-MS.
Figure 2. The model for the coupling of H2A.Z deposition and nucleosome sliding.
The postdoctoral researchers Dr. Yu-Xi Luo and Dr. Xiao-Mei Hou from Dr. Xin-Jian He’s laboratory are the co-first authors of the paper. Dr. Xin-Jian He from National Institute of Biological Sciences is the corresponding author. Other co-authors include Dr. Cui-Jun Zhang, Dr. Lian-Mei Tan, Chang-Rong Shao, Rong-Nan Lin, Yin-Na Su, and Xue-Wei Cai from Dr. Xin-Jian He’s laboratory and Lin Li and Dr. She Chen from the NIBS proteomics facility. The study was supported by the Chinese Ministry of Science and Beijing Municipal Government. All works were completed in NIBS.