Materials and methods br Results and discussions

Materials and methods
Results and discussions
Conclusions In this study, we identified 7 histone acetyltransferases and 12 histone deacetylases in Marchantia polymorpha. The present phylogenetic analysis of MpHATs and MpHDACs provide the insight into the evolutionary relationships of these two groups of protein families among plant and green algae species. We identified groups of sirtuin family and RPD3/HDA1 family proteins specifically in early land plants and green algae, which gives us the hints of potential unknown function of HDACs in lower plant species. MpHATs and MpHDACs showed high sequence identities and similar domain compositions to their homologs in Arabidopsis and rice, suggesting that they would have conserved functional roles in various plant developmental processes. Subcellular localization predictions indicate that most MpHATs and MpHDACs might be localized in both nucleus and cytosol. Additionally, expression analysis of MpHATs and MpHDACs shows that they are expressed constitutively in all tissues and various developmental stages of Marchantia. Different MpHATs and MpHDACs encoding genes show a big difference in gene expression pattern in response to various plant hormones and environmental stresses, suggesting that they may play important functional roles in certain signaling pathways. We concluded that all MpHATs and MpHDACs are functional proteins in Marchantia and play various roles in regulation of histone acetylation/deacetylation. Marchantia could have developed a complex histone acetylation regulatory mechanism to serve for the epigenetic regulation.
Authors’ contribution
Acknowledgment Authors thank MOE Tier 1 grant (RP 1/14 CZ).
Introduction In eukaryotic cells, the basic unit of U-104 sale is the nucleosome. Each nucleosome consists of a histone octamer which contains two molecules of histone H2A, H2B, H3 and H4 wrapped around by 146 bp of DNA. Crystallographic structure has showed that the N-terminal tails of histones overhang the octamer [1]. The highly conserved, flexible N terminus of the histone proteins can undergo plenty of posttranslational modifications which play an important role in regulating chromatin dynamics and eukaryotic transcription. The posttranslational modifications include methylation, acetylation, phosphorylation, ubiquitination, ADP-ribosylation and sumoylation [2]. Among these modifications, the study on acetylation started early and is relatively mature. The dynamic change of histone acetylation is regulated by two enzymes with antagonistic action, histone acetyltransferase (HAT) and histone deacetylase (HDAC) [3]. HATs transfer acetyl moiety of acetyl-CoA to the ε-amino group of lysine residues at the N terminus of histones, and this reaction is reversed by the action of HDACs. Acetylation of core histones is generally associated with “open” chromatin structure and gene activation, whereas deacetylation of core histones is related with “closed” chromatin structure and gene repression [3]. Lysine acetylation in plants besides on histones also occurs in diverse non-histone proteins localized in compartments such as cytoplasm, chloroplasts and mitochondria [4]. A variety of HATs have been investigated in plants and classified into four distinct families including GNAT (GCN5-related N-terminal acetyltransferase) family, p300/CBP (CREB-binding protein) family, MYST (MOZ, Ybf2/Sas3, Sas2, and Tip60) family and TAFII250 (TATA-binding protein-associated factors) family according to their structures [5]. So far, 12 putative HATs are identified from Arabidopsis through homologs search and belong to GNAT family (HAG1/GCN5, HAG2 and HAG3/ELP3), MYST family (HAM1/HAG4 and HAM2/HAG5), p300/CBP family (HAC1/PCAT2, HAC2/PCAT1, HAC4/PCAT3, HAC5/PCAT4, and HAC12) and TAFII250 family (HAF1 and HAF2/TAF1) [5], respectively. Eight HATs were determined in rice [6] grouped into four major families as that in Arabidopsis. Majority of these HATs exist in the form of complexes and are involved in many cellular processes such as transcriptional activation, gene silencing, cell cycle regulation, DNA replication/repair and chromosome assembly [2,7].