The molecular mechanism of chromatin remodeling complex to reshape the structure of nuclear small body is revealed.

Using frozen electroscopy technology, Cai Gang, a professor at China University of Science and Technology, analyzed the three-dimensional structure of the chromatin remodeling SWI/SNF and INO80 complex and its different nuclear small body binding state complex, and revealed the actin common to the SWI/SNF and INO80 complex. The Actin/Arp module, consisting of nucleoprotein-related proteins (Arps), acts as a molecular switch for conformational regulation, regulating the binding of nuclear small bodies and the molecular mechanisms that may regulate the reshaping activity of nuclear small bodies, and the results of the study were recently published in the international journals Protein and Cell Journal and Molecular of Cell Cell Biology.
chromatin structure regulation is of vital importance to gene transcription, cell cycle development, DNA replication, recombination and damage repair of eukaryotes.
enzymes that catalyze changes in chromatin structure, including histone modification (acetylation, methylation, phosphorylation, ubiquity, and ubiquity- etc.) and chromatin remodeling (ATP-dependent DNA shifting enzymes), usually assembled into multi-subqua complexes for function.
multiple histone modification and chromatin remodeling complexes, including Actin and Actin-related proteins (Arps) Actin/Arp modules such as SWI/SNF (BAF in higher organisms), INO80, SWR1, and NuA4/TIP60.
know little about the positioning of these complex complex complex subbases in the complex and its contribution in the assembly and stabilization of the complex, and how to reshape the molecular mechanism of the structure of the nuclear small body.
Cai Gang's team to these difficult problems to develop.
after a lot of system experiments, overcome many difficulties, respectively, obtained the SWI/SNF and INO80 complex complete complex of high-quality biochemical preparation and frozen electron mirror 3D structure, but the resolution is limited by chromatin remodeling the complex significantstructural flexibility, can not be structurally identified the spatial position and interaction of each sub-sub-system.
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in addition, Cai Gang's team analyzed the fine 3D structure of the SWI/SNF Catalytic Core Subcomplex and inthetred of the INO80 Actin/Arp module and its different remodeling states combining the nucleosome base, and found that the Actin/Arp module spent jointly with the SWI/SNF and INO80 complex, first combining the nuclear small body, and helping the nucleosome to load the at-core ATPas.
highly flexible Actin/Arp module not only constitutes the conformation switch of the chromatin remodeling complex combined with the nucleosome, but also has the potential to regulate the activity of SWI/SNF and INO80 chromatin remodeling by directly regulating the conformation of the ATPase domain.
the results are of great significance to reveal the molecular mechanism of chromatin remodeling complex to reshape the structure of nuclear small body, to understand the molecular mechanism of gene expression and regulation, and to the mechanism of cell proliferation, development and differentiation, and to lay a theoretical foundation for the development of new tumor therapy drugs, stem cell differentiation and reprogramming. Zhang Zhianda, ph.D. student at
Cai gang laboratory, and Zhang Rong, the first authors of the two papers, and Cai Gang and researcher Wang Xuexuan are co-authors.
the work was funded by the Fund Committee, the Ministry of Science and Technology and the Hefei National Research Center for Microscale Physical Sciences, and with the instrument and technical support of the Bioimaging Center of the Institute of Biophysics of the Chinese Academy of Sciences.
Source: China University of Science and Technology.