Bacteria and yeasts are suitable model organisms to understand the fundamental mechanisms on cell proliferation. Our laboratory studies the mechanisms behind chromosome and plasmid DNA dynamics in the cell or the mechanism underlies cell shape formation. Genetic methods as well as cell-biological methods were used to observe those intracellular events. We have made several novel observations in cell proliferation mechanism by using fluorescentbased protein or DNA imaging. Especially S. japonicus yeast suits for those cell biological analyses, and studies of hyphal growth and cell cycle add special value on this organism. Novel genetic system has been elucidated by recent our works.
(A) Bacillus subtilis condensin complex is loaded to Spo0J-parS site and rDNA located close to oriC. (B) Image of B. subtilis wild-type strain. (C) Image of double deletion mutant of spo0J and rDNA. Chromosomal DNA was stained with DAPI and pseudocolored with magenta. Since condensin complex cannot be loaded to the chromosome in the double deletion mutant, chromosomal DNA appears to be filamentous.
Yano, K., and Niki, H. (2017). Multiple cis-acting rDNAs contribute to nucleoid separation and recruit the bacterial condensin Smc-ScpAB. Cell Rep 21, 1347-1360.
Aoki, K., and Niki, H. (2017). Release of condensin from mitotic chromosomes requires the Ran-GTP gradient in the reorganized nucleus. Biol Open 6, 1614- 1628.
Seike, T., and Niki, H. (2017). Mating response and construction of heterothallic strains of the fission yeast Schizosaccharomyces octosporus. FEMS Yeast Res 17, doi: 10.1093/femsyr/fox045.