| Project/Area Number |
05304057
|
|---|
| Research Category |
Grant-in-Aid for Co-operative Research (A)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
Developmental biology
|
|---|
| Research Institution | Okazaki National Research Institutes |
|---|
Principal Investigator |
TKEUCHI Ikuo National Institute for Basic Biology, Director-General, 基礎生物学研究所, 所長 (90025239)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
OKAMOTO K Kyoto University, Faculty of Science, Professor, 理学部, 教授 (10029944)
TANAKA Yoshimasa University of Tsukuba, Institute of Biological Science, Professor, 生物科学系, 教授 (80091908)
YANAGISAWA K University of Tsukuba, Institute of Biological Science, Professor, 生物科学系, 教授 (60015899)
MAEDA Yasuo Tohoku University, Faculty of Science, Professor, 理学部, 教授 (50025417)
OCHIAI H Hokkaido University, Faculty of Science, Professor, 理学部, 教授 (10002122)
|
|---|
| Project Period (FY) |
1993 – 1994
|
| Keywords | Cell Differentiation / Morphogenesis / Cell Adhesion / Gene Expression / Cell Cycle / Cellular Slime Mold |
|---|
| Research Abstract |
The controlling mechanisms of morphogenesis and differentiation were investigated using the simple eukaryotes, cellular slime molds.
1.Morphogenesis : Chemotactic stimulation of cells with cAMP or folic acid was found to induce rapid redistribution of myosin through the association of cytoskeleton-related proteins, with the involvement of intracellular Ca^<2+>. Actual measurement of cytosolic Ca^<2+> concentration([Ca^<2+>]_i)by the use of cells transformed with apoaequorin cDNA revealed that chemotactic stimulation caused a rapid increase in[Ca^<2+>]i and that the increase was greater in prestalk cells than in prespore cells. Some of the putative cell adhesion molecules (gp64 and csA) were structurally analyzed in detail in relation to their functions. To understand the mechanism of sexual cell fusion, the gene that specifically expresses in fusion-competent cells were tentatively isolated. Trials were continued to improve the REMI-method conferring blasticidin S resistance to obtain more widely applicable methods.
CELL differentiation : Starvation of cells that were just before the branching point of growth and differentiation (phase-shift[PS]point) in the cell cycle were found to aggregate earlier than the cells that were starved right after passing the PS point. The former was further shown to differentiate into prespore cells while the latter into prestalk cells. Three kinds of the genes that were specifically expressed around the PS point were also isolated and identified. Four species of proteins were demonstrated to change dramatically in the degree of phosphorylation near the PS point. Some of the developmentally regulated genes were found to be induced by yet unidentified factor (s) secreted from cells. The newly isolated gene dutA belonged to this class and was shown to function probably without being translated into protein. The factor that induced prespore-specific genes was purified to homogeneity, giving an apparent molecular mass of about 190Kd.
|
