Yasuhisa Matsui


Director of Cell Resource Center, Professor Yasuhisa MATSUI
Assistant Professor Yohe HAYASHI
Assistant Professor Kei OHTUSKA
Assistant Professor Hiromitsu OHTA
Assistant Professor Yukiko TANDO
Technical Staff Ikue AIHARA
Technical Staff Yumi MATSUOKA
Technical Assistant Fujimi KOIZUMI
Technical Assistant Yumi (ITO) MATSUOKA
Technical Assistant Asuka TAKEHARA

The purpose of the Cell Resource Center for Biomedical Research is the collection, establishment, quality control, distribution of useful cell lines, and the construction of a database for researchers. The cell lines include transplantable animal cells such as the Yoshida sarcoma and the rat ascites hepatoma (AH series); also included are human, murine, and hybridoma cells.

Our research goal is to elucidate the molecular mechanisms of mouse primordial germ cell (PGC) formation and their subsequent development. These studies are meaningful not only for basic research interests for germ cell development, but also for furthering our understanding of possible applications of germ cells and pluripotent stem cells in practical science.

Research Topics
•Identification and functional analysis of genes involved in germ cell formation and differentiation.
•Epigenomic analysis in germ cells.
•Molecular mechanisms that regulate conversion between germ cells and pluripotential stem cells.

Latest Achievement:
An approach to reconstitute germ cell-like characteristics in somatic cells in culture.
Germ cells acquire the totipotency through fertilization to generate individuals of successive generations, but somatic cells do not have such potential. To understand the mysterious cellular characteristics of germ cells at the molecular level, we attempted to directly convert mouse embryonic fibroblasts (MEFs) into primordial germ cells by defined factors.
We first planned to express pluripotency genes and to globally induce germ cell-specific genes in MEFs for direct reprogramming of MEFs into PGCs. After testing several conditions, we successfully induced the expression of some germ cell-specific genes by transfection of plasmid expressing Yamanaka factors (Oct4, Sox2, Klf4, c-Myc) and by inhibition of some repressive epigenetic modifications including DNA methylation and histone H3K27 tri-metylation (H3K27me3) by RNAi, or by small-molecule compounds. Moreover, this condition did not induce somatic genes expression, and it suggests that induction of germ cell-specific genes in this condition is not caused by non-specific transcription activation. Meanwhile, in this condition, some tissue-specific genes such as nervous system-specific genes or immune system-specific genes other than germ cell-specific genes were also induced.
These results suggest a possibility that the expression of tissue-specific genes including germ cell-specific genes in MEFs is selectively repressed by the epigenetic modifications such as DNA methylation or H3K27me3.

Screenshot (154)

The method for alteration of a gene expression profile of MEFs towards that of germ cells in culture (above).
We have succeeded in altering a gene expression profile of mouse embryonic fibroblasts (MEFs) to that of germ cells in culture by addition of small-molecule compounds inhibiting repressive histone modifications and by inhibition of Dnmt1 expression by RNAi. Red: germ cell maker (Dazl), Blue: nucleus maker (DAPI). Sekinaka,T., Hayashi, Y., Noce, T., Niwa, H., Matsui, Y. Selective de-repression of germ cell-specific genes in mouse embryonic fibroblasts in a permissive epigenetic environment. Scientific Reports 6:32932 (2016). DOI: 10.1038/srep32932.