Sekiya Takeshi, Murano Kensaku, Kato Kohsuke, Kawaguchi Atsushi, Nagata Kyosuke
Department of Infection Biology Faculty of Medicine and Graduate School of Comprehensive Human Science University of Tsukuba Japan.
Department of Molecular Biology Keio University School of Medicine Tokyo Japan.
FEBS Open Bio. 2017 Jan 25;7(3):397-404. doi: 10.1002/2211-5463.12189. eCollection 2017 Mar.
During mitosis, higher order chromatin structures are disrupted and chromosomes are condensed to achieve accurate chromosome segregation. CCCTC-binding factor (CTCF) is a highly conserved and ubiquitously expressed C2H2-type zinc finger protein which is considered to be involved in epigenetic memory through regulation of higher order chromatin architecture. However, the regulatory mechanism of CTCF in mitosis is still unclear. Here we found that the DNA-binding activity of CTCF is regulated in a phosphorylation-dependent manner during mitosis. The linker domains of the CTCF zinc finger domain were found to be phosphorylated during mitosis. The phosphorylation of linker domains impaired the DNA-binding activity . Mutation analyses showed that amino acid residues (Thr289, Thr317, Thr346, Thr374, Ser402, Ser461, and Thr518) located in the linker domains were phosphorylated during mitosis. Based on these results, we propose that the mitotic phosphorylation of the linker domains of CTCF is important for the dissociation of CTCF from mitotic chromatin.
在有丝分裂期间，高阶染色质结构被破坏，染色体凝聚以实现精确的染色体分离。CCCTC结合因子（CTCF）是一种高度保守且广泛表达的C2H2型锌指蛋白，被认为通过调节高阶染色质结构参与表观遗传记忆。然而，CTCF在有丝分裂中的调控机制仍不清楚。在此我们发现，CTCF的DNA结合活性在有丝分裂期间以磷酸化依赖的方式受到调控。我们发现CTCF锌指结构域的连接区在有丝分裂期间被磷酸化。连接区的磷酸化损害了DNA结合活性。突变分析表明，位于连接区的氨基酸残基（苏氨酸289、苏氨酸317、苏氨酸346、苏氨酸374、丝氨酸402、丝氨酸461和苏氨酸518）在有丝分裂期间被磷酸化。基于这些结果，我们提出CTCF连接区的有丝分裂磷酸化对于CTCF从有丝分裂染色质上解离很重要。
