Structural And Functional Study Of The Methylation Complex Set1/COMPASS

In eukaryotic transcription,histone modifications(including phosphorylation,acetylation,methylation,and ubiquitination and etc)are crucial regulators for related biological process.In Eukaryotes,chromatin modifying complexes catalyze covalent chemical modifications of the histone tails,formed functional transcription regulation network,named histone code.Especially,the N terminus of highly conserved histone H3 is subject to major modifications,we focused on investigating the methylation of H3K4 by Set1/COMPASS in S.cerevisiae,there is only one enzyme that methylase H3K4.Despite the function research of the COMPASS,little was known about the overall structure,which can provide bright insight of this complex and the biological mechanism,highlighting the significance of investigating its structure.Combined with EM technology,we reconstructed the first overall 3D structure of Setl/COMPASS complex,and nanogold labeling data support us few important subunits localization,in vitro assembling experiments also reveal the possible substrate binding site of Setl/COMPASS complex.We were surprised to find,the elongation factor Pafl complex can block the H3K4 methylation by Setl in vitro,which can also be relieved by the deletion of Rtfl subunit,reveled the significant role of Pafl,especially the subunit Rtfl,in regulating the methylation of H3K4 by Setl/COMPASS complex.