- 著者
- Masato Hino Daisuke Morokuma Hiroaki Mon Jae Man Lee Takahiro Kusakabe
- 出版者
- (社)日本蚕糸学会
- 雑誌
- Journal of Insect Biotechnology and Sericology (ISSN:13468073)
- 巻号頁・発行日
- vol.85, no.2, pp.2_021-2_029, 2016 (Released:2016-10-12)
- 参考文献数
- 29
DNA replication is one of key event in cell-cycle progression, yet due to their importance and lethality, the chronological phenotypes of DNA synthesis machineries after the depletion of corresponding genes have proved difficult to study. In the present study, mRNAs for three DNA polymerases, a clamp, and three clamp loaders were gradually depleted from cultured silkworm cells by soaking RNAi. Interestingly, the depletion of these DNA synthesis factors had different effects on the cell growth rate and arrest of cell-cycle progression during time-lapse observation. The depletion of DNA polymerases immediately arrested the cell-cycle progression at the S phase, while that of PCNA, a DNA clamp, required more time to slow cell growth and finally induced apoptosis. Surprisingly, silkworm cells continued to undergo several rounds of cell division when the components of clamp loaders were knocked down.
- 著者
- Hitoshi Mitsunobu Makiko Izumi Kazuhiro Iiyama Hiroyuki Jikuya Jae Man Lee Hiroaki Mon Yutaka Kawaguchi Takahiro Kusakabe
- 出版者
- (社)日本蚕糸学会
- 雑誌
- Journal of Insect Biotechnology and Sericology (ISSN:13468073)
- 巻号頁・発行日
- vol.79, no.3, pp.3_075-3_083, 2010 (Released:2011-09-12)
- 参考文献数
- 31
In eukaryotes, genomic DNA is wrapped around an octamer of the core histone proteins H2A, H2B, H3 and H4. Silkworms have been known to bear holocentric chromosomes and their regulatory mechanisms of chromatin remodeling remain unclear. We have cloned the silkworm canonical core histones and their variants. The H2A variants, H2AX and H2AZ, were highly conserved in the silkworm, whereas the fly has only one H2A variant, H2Av, which is a chimera of H2AX and H2AZ with the function of both molecules. In the silkworm, all histones except for H2AX were ubiquitously expressed in all tested tissues, and H2AX was expressed only in the genital organs. A subcellular localization analysis of the cloned histones using an EGFP fusion construction demonstrated that the behaviors of the histones are the same as those of genomic DNA throughout the cell cycle. The fluorescence intensities of H2AX and H3.3 were weaker than those of the other histones. The incorporation of these histones into chromatin might be restricted due to their specific function in DNA repair and transcription activity. There were two H3 variants, H3.2 and H3.3, in the silkworm; H3.1 was not present. Lysine 9 on H3 was methylated and acetylated in silkworms bearing holocentric chromosomes.