Graduate School of Frontier Biosciences, Osaka University

Japanese

Colloquium 245

Speaker Tetsuya Hori (Associate professor (FBS Lab. of Chromosome Biology (Fukagawa Lab.)))
Title Epigenetic regulation on vertebrate centromere
Date Thu., July 16 , 2020, 12:15~13:00
Place Zoom (on line):We will announce the Meeting URL, ID and Password until the day before the each colloquium by Email.
Host Name: Tetsuya Hori (Associate professor/ Lab. of Chromosome Biology (Fukagawa Lab.)
Tel:06-6879-4425
E-mail:thori@fbs.osaka-u.ac.jp
Language English

Title/Abstract

Epigenetic regulation on vertebrate centromere

The centromere is an essential genome region where the kinetochore is established for faithful chromosome segregation. In most organisms, centromeres are specified by sequence-independent epigenetic mechanisms through the deposition of histone H3-variant CENP-A into chromatin. Therefore, it is critical to know how CENP-A is deposited into centromeric chromatin. We previously showed that the chicken Mis18 complex directly binds to the CENP-A nucleosome and is recognized by the pre-deposition CENP-A-H4-HJURP (CENP-A specific chaperon) complex for new CENP-A incorporation. However, it is still unknown how the pre-deposition CENP-A-H4-HJURP complex correctly transfers the CENP-A into centromeric chromatin and how the CENP-A nucleosome triggers to assemble the kinetochore in the vertebrate cells. Here, we analyzed various CENP-A domains in the chicken DT40 cells, using a gene complementation assay. We found that while both N- and C-terminal tails of CENP-A were dispensable, the alpha-1 helix region near CATD (CENP-A targeting domain) was essential for CENP-A deposition and centromere maintenance in chicken DT40 cells, which is not the case for human CENP-A. Combined biochemical data, we propose that the essentiality of CENP-A depends on its binding mode to HJURP, which is variable during evolution.


Back