[1FT-3] Protein/cellular functions, Imaging (1P-49～1P-61)

[1P-50*] Investigation of histone H2A topography and its spatiotemporal dynamics in DNA compaction using high-speed atomic force microscopy

^○Goro Nishide¹, Keesiang Lim^2,3, Akiko Kobayashi^2,3, Masaharu Hazawa^2,3, Takahiro Nakayama², Noriyuki Kodera², Toshio Ando², Wong Richard^2,3 (1.Div. Nano, Grad. FS, Kanazawa Univ. , 2.WPI-NanoLSI, INFINITI, Kanazawa Univ., 3.Cell-Bio, INFINITI, Kanazawa Univ.)

DNA wrapping on histone octamers is crucial for DNA compaction to store enormous biological data in nuclei. Two copies each of histones H2A, H2B, H3 and H4 are collected by histone chaperones and chromatin remodelers. Each nucleosome is built up of 50 nm of DNA (147 bp) that is wrapped 1.7 times around a histone octamer. Nucleosomes are dynamic as they can either relocate or spontaneously breathe. DNA-histone interaction is mainly mediated by electrostatic force, and manipulation of this force is essential for regulating biological activities such as DNA repair and gene expression. Much less is known about the dynamics of interaction between a single histone and DNA, due to lack of suitable nanoscopic imaging tools. Here we investigate the topology properties of H2A and its interaction with plasmid DNA in physiological buffer using high-speed atomic force microscopy (HS-AFM). HS-AFM images show that H2A topology resembles to its simulated images, in which H2A tail can be clearly seen. Ongoing works regarding HS-AFM imaging of interaction between H2A and plasmid DNA will be discussed during poster presentation.