| Co-Investigator(Kenkyū-buntansha) |
MINAMI Yasuhiro Kobe Univ., School.Med., Ass.Professor, 医学部, 助教授 (70229772)
YOSHIDA Minoru The Univ.Tokyo, Grad.Sch.Agr., Ass.Professor, 農学生命研究科, 助教授 (80191617)
TANAKA Kazuma Osaka Univ., School.Med., Ass.Professor, 医学部, 助教授 (60188290)
ARAKI Hiroyuki Osaka Univ., Inst. Micubid.Diseaus., Ass.Professor, 微生物病研究所, 助教授 (20151160)
HIYAKAWA Tokichi Hiroshima Univ., Dept.Ferment.Tech., Professor, 工学部, 教授 (10116676)
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| Research Abstract |
Our aims of this research project were to elucidate the molecular mechanisms of G1 progression and G1/S transition. To reach this goal, some prominent investigators devoted to this field were supported to proceed their work. During the course of this program, the following new findings were made.
1. Gene functioning at the end of mitosis were isolated by Tohe's group. They are small G protein gene. (TEM1), protein kinase gene (CDC15), protein phosphatase gene (CDC14) and SPO12. A model of network consisting of these genes are presented.
2. Protein phosphatase 2B (calcineurin) was found to antagonize the function of the cAMP pathway which suppresses the expression of the Na+ pump gene. Interactions between calcineurin and MAP kinase cascade were newly found by analyzing mutants displaying a similar phenotype as that of a calcineurin deletion mutant. These were done by Miyakawa's group.
3. Yoshida's group has been screened inhibitors for cell cycle progression. One of their isolates, trycostatin, were found to inhibit histone deacetylase. Administration of this drug induced gelsolin and histone H1 variant. They also obtained drugs which specifically inhibited the growth of cdc13, cdc25, and wee1 of S.pombe.
4. Minami's group devoted to analyze the IL-2 signal transduction system. They reconstituted this system in fibroblast and found new tyrosin kinases that cooperatively function with IL-2. One of them, Sylc induced expression of c-myc in responding to IL-2, and the other enzyme, Jak2 was found to be needed for G1/S transition.
5. Tanaka's group elucidated that Rho-type GTPase, Rho1, is localized at a bud and colocalized with actin. They also found that PKC is on of the effecters of Rho1. Two regulatory proteins of Rho1 were also identified.
6. The largest subunit of DNA polymerase II is POL1. Araki's group isolated a muticopy suppressor of pol2-18 and found that this is a new essential gene designated MDB11. This gene exerts its function at the checkpoint during S phase.
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