Construction of constitutive heterochromatin and facultative heterochromatin

2018 Fiscal Year Final Research Report

• Project/Area Number: 16H04739
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Molecular biology
• Research Institution: Osaka University (2017-2018); Hokkaido University (2016)
• Principal Investigator: Chikashi OBUSE 大阪大学, 理学研究科, 教授 (00273855)
• Research Collaborator: NAGAO Koji ; Isobe Shin-Ya ; Sado Takashi
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: ヘテロクロマチン / エピジェネティクス / ヒストン修飾

Outline of Final Research Achievements

Heterochromatin is defined into two categories; constitutive heterochromatin based on H3K9me3 which is responsible for the formation of stable heterochromatin, such as centromere and telomere, and facultative heterochromatin based on H3K27me3 which is responsible for developmentally formed heterochromatin, such as inactive X chromosome and Hox gene clusters. Aim of this study is to understand common and different points between two heterochromatins. Our results showed that H3K9me3 histone mark was on inactive X chromosome and formed domains as well as H3K27me3, and that the H3K9me3 domains were shrunk and replaced to H3K27me3 by knockdown/out of genes which are responsible for compaction of heterochromatin. These results suggest that there is no definition such as constitutive and facultative, rather H3K9me3 and H3K27me3 domains are constituents for the formation of functional heterochromatin to regulate gene expression properly.

Free Research Field

分子細胞生物学

Academic Significance and Societal Importance of the Research Achievements

これまで、セントロメアやテロメアなどの構成的なヘテロクロマチンと、発生・分化依存的な条件的ヘテロクロマチンは、同じ凝縮したクロマチン構造をとりながら、基盤となるヒストン修飾や構成する因子が異なると考えられてきた。本課題により、構成的なヘテロクロマチンの形成に必要と考えられているヒストン修飾や因子が、条件的ヘテロクロマチン形成の一要素であることが示唆された。これらの成果は、今後遺伝子発現制御の要であるヘテロクロマチンを理解する上で重要な仮説であると考えられる。