Molecular Mechanisms of Differentiation and Proliferation Switches

从细胞周期的角度对细胞增殖和细胞分化的调控机制进行了研究，得到了以下结果：(1)秀丽隐杆线虫hch-1基因，控制孵化和细胞迁移，编码BMP-1和TOLLOID相关蛋白（Katsura）。(2) MAPKK/MAPK级联是非洲爪蟾卵母细胞成熟起始的必要和充分条件（Nishida）。(3)利用磷酸化蛋白特异性抗体，Cdc2激酶、c激酶和CF激酶在细胞周期中磷酸化中间丝蛋白（Inagaki）。(4)在静止细胞中表达DELTAFosB，通过降低细胞周期蛋白E和CDK2 mrna的降解速率，从而增加细胞周期蛋白E和CDK2 mrna，从而启动细胞增殖（Nakabeppu）。(5)复制因子C参与S期检查点控制，因为其亚基基因RFC5的ts突变被SPK1/Rad53激酶的过量产生所抑制（Sugimoto）。(6) epi-1是一种抑制人类上皮细胞生长的特异性基因，类似于疣/大肿瘤抑制基因，一种果蝇肿瘤抑制基因（Masui）。(7)新的tgf - β受体亚型、14-4-3蛋白和HCP1蛋白的人类cdna可增强酵母细胞中肌醇合成酶的转录（Nikawa）。通过不同材料和方法获得的结果揭示了这些开关在细胞增殖/分化中的基本和物种特异性机制。

Research on the control mechanisms of cell-proliferation and cell-differentiation was performed from the viewpoint of cell-cycle, and the following results were obtained. (1) C.elegans hch-1 gene, which controls hatching and cell-migration, encodes a protein related to BMP-1 and TOLLOID (Katsura). (2) The MAPKK/MAPK cascade is necessary and sufficient for the initiation of Xenopus oocyte maturation (Nishida). (3) Cdc2 kinase, Ckinase and CF kinase were shown to phosphorylate intermediate filament proteins during the cell cycle, by using phosphoprotein-specific antibodies (Inagaki). (4) Expression of DELTAFosB in quiescent cells initiates cell proliferation through increase of cyclin E and CDK2 mRNAs by decrease of their degradation rate (Nakabeppu). (5) Replication factor C is involved in the S phase check-point control, because a ts mutation in its subunit gene RFC5 is suppressed by the overproduction of SPK1/Rad53 kinase (Sugimoto). (6) epi-1, a gene specific for the growth arrest of human epithelial cells, resembles warts/large tumor suppressor, a Drosophila tumor suppressor gene (Masui). (7) Human cDNAs of a new TGF-beta receptor subtype, a 14-4-3 protein and a novel protein HCP1, enhance the transcription of inositol-synthesizing enzymes in yeast cells (Nikawa). The results obtained by diverse materials and methods revealed the basic and species-specific mechanisms of the switches in cell-proliferation/differentiation.