Dear Editor,Eukaryotic genome packs into highly condensed chromatin,in which genomic DNA wraps around histone octamer formed by evolutionarily conserved histone proteins H2A,H2B,H3,and H4.The histone variant H2A.Z primarily exists within nucleosomes that flank gene promoters,centromeres,and chromatin boundaries.The H2A.Z-containing nucleosomes undergo rapid turnover,which is important for the regulation of gene expression,DNA repair,and chromosome stability1.The deposition of H2A.Z into genome is uniquely dependent on the SWI/SNF (switch/sucrose non-fermentable)-related Swr1 complex (referred to as Swr1-C hereafter) in yeast and SNF2-Related CBP Activator Protein (SRCAP) complex (referred to as SRCAP-C hereafter) in human.Swr1-C/SRCAP-C incorporates H2A.Z/H2B dimer into canonical nucleosomes coupled with the eviction of H2A/H2B dimer in a stepwise exchange manner2-4.
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We thank Center for Biological Imaging of Institute of Biophysics of Chinese Academy of Sciences and National Center for Protein Science Shanghai for the support on cryo-EM data collection and data analyses.We thank staff members at Biomedical Core Facility,Fudan University for their help with mass2016YFA0500700;the National Natural Science Foundation of China31830107,U1432242,31425008;the National Program for support of Top-Notch Young Professionals;the Strategic Priority Research Program of the Chinese Academy of SciencesXDB08000000