Grant-in-Aid for Overseas Scientific Survey.
|Research Institution||National Institute for Basic Biology|
TAKEUCHI Ikuo National Institute for Basic Biology, 基礎生物学研究所, 所長 (90025239)
WILLIAMS J. 英国帝国癌研究所, 教授
田坂 昌生 京都大岸, 理学部, 助教授 (90179680)
TASAKA Masao Kyoto University, Faculty of Science
JEFFREY G. Williams Imperial Cancer Research Fund
|Project Fiscal Year
1989 – 1991
Completed(Fiscal Year 1991)
|Budget Amount *help
¥6,400,000 (Direct Cost : ¥6,400,000)
Fiscal Year 1991 : ¥1,000,000 (Direct Cost : ¥1,000,000)
Fiscal Year 1990 : ¥2,800,000 (Direct Cost : ¥2,800,000)
Fiscal Year 1989 : ¥2,600,000 (Direct Cost : ¥2,600,000)
|Keywords||Cellular slime mold / Cell differentiation / Pattern formation / Cell sorting / Gene expression / 細胞性粘菌 / 細胞分化 / パタ-ン形成 / 細胞選別 / 遺伝子発現|
In the development of cellular slime molds, cells aggregate to form a tissue, in which two types of cells (prestalk and prespore) differentiate in the anterior and the posterior parts. To elucidate the mechanisms of cell differentiation and pattem formation, we made the following studies.
(1) We have shown that cells cultured in liquid in a roller tube form an agglutinate in which prestalk, and prespore cells exhibit a definite pattern of differentiation without undergoing morphogenesis. Williams made a similar culture of cells whose expression of prestalk-specific ecmA and ecmB genes can be histochemically detected by BATA-galactosidase activity. In the agglutinates forined, cells expressing ecmA first arose randomly and then were collected to the center, while those expressing ecmB appeared on the surface layers. The result is consistent with the previous one obtained with the pattem of prespore differentiation and indicates that the differentiation pattem is tonned by sorting out of
(2) We have previously shown that the upstream region between -442 and -349 bp of presporespecific Dp87 gene is important for its expression. When this region is fused with the basal promoter of slime mold actin gene, the chimera gene was expressed from the vegetative stage and no difference in expression was detected between prestalk and prespore cells. This suggests that the upstream region only enhances the amount of transcription, but that cell-type-and development-specific expression is regulated by the region below -349 bp.
(3) Expression of Dp87 gene during normal development was examined by using cells transformed with the promoter of Dp87 fused with BATA-galactosidase gene. Cells expressing Dp87 first appeared randomly in the aggregation streams and were later accumulated in the basal part of the aggregation centers, continuing the above notion that the differentiation pattem is formed by sorting out of differentiated cells.