1992 Fiscal Year Final Research Report Summary
Mechanism of formation of differentiation pattern in the cellular slime mold
| Project/Area Number |
02454018
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
植物形態・分類学
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| Research Institution | Okazaki National Research Institutes |
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Principal Investigator |
TAKEUCHI Ikuo National Institute for Basic Biology, Director-General, 基礎生物学研究所, 所長 (90025239)
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| Co-Investigator(Kenkyū-buntansha) |
TASAKA M Kyoto University, Faculty of Science Associate Professor, 理学部, 助教授 (90179680)
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| Project Period (FY) |
1990 – 1992
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| Keywords | Cell Differentiation / Pattern Formation / Cell-type-specific Gene / Gene Transcription Control / Cellular Slime Mold |
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| Research Abstract |
In the development of the cellular slime molds, cells aggregate to form a tissue, in which two types of cells (prestalk and prespore) differentiate and occupy the anterior and the postirior parts of the tissue. To elucidate the mechanism of pattern formation in these organisms, we made following studies.
1. Studies on expression of prespore-specific Dp87 gene, previously isolated by us, revealed that upon differentiation of prespore cells, the gene was expressed earliest among the other prespore genes. Examination of the gene expression in the tissue using a chimeric gene consiting of Dp87 promoter and beta-galactosidase gene showed that prespore cells first appeared randomly in early aggregation streams. As development proceeded, however, they were sorted out to the bottom part of the tissue. These substantiate our claim that cells which have differentiated independent of their positions in the tissue are sorted out to form a pattern of differentiation.
2. We allowed E.coli to produce a large amount of Dp87 gene product, against which a specific antibody was produced and used for examining its developmental changes. The gene product first appeared as 81kD protein in ER of aggregating cells and was then modified to become 83kD protein which accumulated in fibrous material of prespore vesicles of slug cells. Upon spore formation, the protein was exocytosed and constituted the interspore matrix.
3. We obtained a mutant strain which lacks in Dp87 gene, by using homologous recombination. The mutant appeared normal both structurally and functionally.
4. We examined the 5'-upstream region of Dp87 gene for its transcriptional regulation and found four regions for positive control of prespore-specific transcription, one for negative control of non-prespore transcription, and another for positive control of cell type-independent transcription, indicating that they are involved in cell-type- and developmental stage-specific regulation of the gene transcription.
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