1990 Fiscal Year Final Research Report Summary
Regulatory Mechanisms of Cell Division in Early Development
| Project/Area Number |
01304005
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| Research Category |
Grant-in-Aid for Co-operative Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
動物発生・生理学
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| Research Institution | Hokkaido University |
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Principal Investigator |
KATAGIRI Chiaki Hokkaido Univ. FAC. SCI., PROF., 理学部, 教授 (90000827)
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| Co-Investigator(Kenkyū-buntansha) |
SAWAI Tsuyoshi Yamagata Univ., COLL. GEN. EDUC., PROF., 教養部, 教授 (10007239)
MABUCHI Issei Univ. Tokyo, COLL. ARTS, SCI., ASS. PROF., 教養学部, 助教授 (40012520)
KISHIMOTO Takeo Tokyo Inst. TECH. FAC. SCI., PROF., 理学部, 教授 (00124222)
NEMOTO Shin-ichi Ochanomizu Univ. FAC. SCI., ASS. PROF., 理学部, 助教授 (60017209)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Germinal Vesicle / Maturation Promoting Factor / Cyclin / Nucleoplasmin / Hi Histone Subtype / Contractile Ring / Actin / Cleavage Furrow |
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| Research Abstract |
A technique was devised to isolate a large number of germinal vesicles (GV) from the starfish oocytes, with which the system was established for biochemical analyses of cyclic cytoplasmic activities that accompany cell cycles during maturation and cleavage divisions. Tha maturation promoting factor (MPF) in starfish oocytes is defined as the histone H1 kinase activity which is based on the phosphorylated cdc2 protein associated with the cyclin. The cyclic proteolysis of cyclin results in cessation of M-phase in cell cycles. Remodeling of nuclear basic proteins during fertilization and cleavage stages was analyzed by the cell-free system employing lysolecithin-permeabilized sperm nuclei incubated in the cytosls of amphibian eggs. During pronulcear formation, the protamines are quickly removed non-enzymatically by the nucleoplasmin derived from the GV, followed by an addition of nucleosomal core histones and a subtype of histone H1 (H1X) which is specific to the cleavage stage nuclear chromatin. The contractile ring occurring during cytokinesis of sea urchin eggs is formed by an organized assembly of actin fibers which is based on the phosphorylated myosin light chains. Of several protein s that are thought to participate in regulation of contractile ring formation, determinations were made of the binding site on the actin molecule of depactin as well as the primary structure of profilin, an inhibitor of G-actin polymerization. Both the cleavage furrow-inducing activity and the furrow formation in the amphibian eggs were inhibited by colchicine and vinblastine, suggesting a direct involvement of microtubule system in the formation of contractile system of the cleavage furrow.
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