Biology subjects

Kohzaki, H.

Publications and source records attributed to Kohzaki, H..

3 recordsLinked to original sources

bioRxiv2019

A transcription factor Abf1 facilitates ORC binding onto the Saccharomyces cerevisiae replication origin via histone acetylase Gcn5

Chromatin structure has been implicated in the regulation of DNA replication but the molecular mechanism involved is unclear. In this study, we observed that binding of the transcription factor Abf1 to the replication origin ARS1 facilitated the association of the origin recognition complex (ORC) with ARS1 using genetic interaction analysis and ChIP assay. The histone acetyltransferases (HATs), Gcn5 and Esa1, were also loaded onto ARS1 in an Abf1 site-dependent manner, where they were then responsible for acetylating histone H3 lysine 18 (H3K18) and histone H4 lysine 12 (H4K12), respectively. Interestingly, Abf1 interacted with Gcn5, while ORC interacted with Esa1. Indeed the B3 element showed genetic interaction with Gcn5 and Rpd3 not with Esa1, Act3 and Tra1.\n\nThese data suggest that Gcn5, which is recruited by Abf1, alters chromatin structure via histone acetylation and facilitates the loading of ORC. We therefore propose that transcription factors regulate chromatin structure at replication origins by recruiting chromatin-modifying proteins, such as HATs, to load the initiator.

genetics↗

bioRxiv2018

Epigenetic regulation affects fertility in Drosophila: toward the production of infertility models.

We have revealed that the chorion gene clusters amplify by repeatedly initiating DNA replication from chorion gene amplification origins in the response to developmental signals, through the transcription factors in Drosophila ovarian follicle cells. Orc1, Orc2, and Cdc6 are forms of DNA replication machinery, which are conserved from yeast to humans; and Orc1 and Orc2 mutants are lethal. Overexpression of Orc1 or Orc2 (subunits of the origin recognition complex) led to female sterility, but overexpression of Cdc6 (an Orc family member) or GFP did not. We propose that DNA replication machinery contributes to development.\n\nRecently, we found that H3K4 was trimethylated at chorion gene amplification origins, but not at the Act1 locus. Overexpression of Lsd1H3K4 dimethylase and Lid H3K4 trimethylase are female sterile but not a Lid mutant. These results showed that epigenetic regulation affected fertility. Screening strategies using Drosophila flies could also lead to the development of drugs that reduce sterility and epigenetic effects related histone modification.\n\nSummary statementThere are approximately 470,000 infertile individuals in Japan. We knockowned the prereplicative complex components and demethlases during Drosophila ovary development. In these drospohila, we could be the model of infertile.

molecular biology↗

bioRxiv2017

The function of the prereplicative complex and SCF complex components during Drosophila wing development

Chromosomal DNA replication machinery functions in the growing cells and organs in multicellular organisms. We previously demonstrated that its knockdown in several tissues of Drosophila led to a rough eye phenotype, the loss of bristles in the eye and female sterile. In this paper, we investigated in detail the wing phenotype using RNAi flies, and observed that the knockdown not only of Mcm10 but also of some other prereplicative complex components demonstrated wing phenotypes, using Gal4-driver flies. Surprisingly, some SCF complex components, which control cell cycle progression via protein degradation, also showed the wing phenotype. These results showed that the DNA replication machinery contributes to wing development independent of growth, probably through defects in DNA replication and protein degradation at specific places and times.\n\nSummary statementWe recently outlined the prereplicative complex components, including Mcm10 and SCF complex functions, during Drosophila wing development. In this paper, we detail these findings.

genetics↗