FBS Colloquia No.197Laboratory of Chromosome Biology
| Seminar or Lecture |
Genome wide analysis of Centromere region in interphase nuclei Kohei Nishimura [Laboratory of Chromosome Biology] Molecular dissection of CENP-A nucleosome recognition by a centromere protein, CENP-C Mariko Ariyoshi [Laboratory of Chromosome Biology] |
|---|---|
| Date and Time | Wednesday, October 24, 2018, 12:15-13:00 |
| Place | 2F Seminar room, BioSystems Building |
| Contact |
Tetsuya Hori |
Genome wide analysis of Centromere region in interphase nuclei
The centromere is a specialized locus associated with centromere factors CENP-A nucleosome and CCAN and it functions in chromosomal segregation via kinetochore formation during mitosis. The centromere is still a special locus in interphase nuclei, but centromere structure and function in interphase are unknown. To understand them, we focused on a genome wide analysis of centromere regions. The mammals human and mouse have highly conserved repetitive sequences at centromere regions, which makes it difficult to apply a genome wide analysis of them. However, chicken cells have centromeres with non-repetitive sequences at chromosomes 5, 27 and Z. In addition, we have many DT40 cell lines that have neocentromere with non-repetitive sequences at various loci on chromosome Z (Shang WH et al., Dev Cell, 2013). This is a great advantage of investigating centromere structure and function in interphase. By applying 4C-seq (Circular Chromosome Conformation Capture) analysis of these cell lines, charismatic features of interphase centromere structure are elucidated.
Molecular dissection of CENP-A nucleosome recognition by a centromere protein, CENP-C
Centromere is an indispensable structural feature of chromatin for accurate cell cycle progression. The primary function of centromere is providing a platform for assembly of the kinetochore super-protein complex driving chromosome segregation. The histone H3 variant, CENP-A is a well-known epigenetic marker for the centromere specification. One of the kinetochore proteins, CENP-C directly interacts with CENP-A nucleosome and secures the kinetochore formation on centromeres. We previously revealed that the middle region of chicken CENP-C is involved in centromere localization during interphase, while the C-terminal region of CENP- C is required for centromere localization during mitosis. These findings imply that kinetochore assembly is partly regulated through conformational changes of CENP-C. To understand how the molecular interaction mode of CENP-C is regulated in a cell cycle dependent manner, we have investigated structural and biochemical properties of chicken CENP-C and its CENP-A nucleosome binding. To gain structural information, we have established in vitro reconstitution and purification system of the CENP-C:CENP-A nucleosome complex suitable for CryoEM analysis. I will present our recent data about CENP-A nucleosome recognition by CENP-C.
