TY - JOUR T1 - Somatic role of SYCE2: an insulator that dissociates HP1α from H3K9me3 and potentiates DNA repair JF - Life Science Alliance JO - Life Sci. Alliance DO - 10.26508/lsa.201800021 VL - 1 IS - 3 SP - e201800021 AU - Noriko Hosoya AU - Masato Ono AU - Kiyoshi Miyagawa Y1 - 2018/06/01 UR - https://www.life-science-alliance.org/content/1/3/e201800021.abstract N2 - The synaptonemal complex is a proteinaceous structure essential for meiotic recombination, and its components have been assumed to play a role exclusively in the germ line. However, SYCE2, a component constituting the synaptonemal complex, is expressed at varying levels in somatic cells. Considering its potent protein-binding activities, it may be possible that SYCE2 plays a somatic role by affecting nuclear functions. Here, we show that SYCE2 constitutively insulates HP1α from trimethylated histone H3 lysine 9 (H3K9me3) to promote DNA double-strand break repair. Unlike other HP1α-binding proteins, which use the canonical PXVXL motifs for their bindings, SYCE2 interacts with the chromoshadow domain of HP1α through its N-terminal hydrophobic sequence. SYCE2 reduces HP1α-H3K9me3 binding without affecting H3K9me3 levels and potentiates ataxia telangiectasia mutated–mediated double-strand break repair activity even in the absence of exogenous DNA damage. Such a somatic role of SYCE2 is ubiquitously observed even if its expression levels are low. These findings suggest that SYCE2 plays a somatic role in the link between the nuclear microenvironment and the DNA damage response potentials as a scaffold of HP1α localization. ER -