| Project/Area Number |
16370098
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Developmental biology
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| Research Institution | RIKEN |
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Principal Investigator |
NISHIWAKI Kiyoji RIKEN, Laboratory for Cell Migration, Team Leader, 細胞移動研究チーム, チームリーダー (30342827)
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| Co-Investigator(Kenkyū-buntansha) |
KUBOTA Yukihiko RIKEN, Laboratory for Cell Migration, Researcher, 細胞移動研究チーム, 研究員 (70333325)
IHARA Shinji RIKEN, Laboratory for Cell Migration, Researcher, 細胞移動研究チーム, 基礎科学特別研究員 (70373272)
大蔵 清貴 独立行政法人理化学研究所, 細胞移動研究チーム, 研究員
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥15,600,000 (Direct Cost: ¥15,600,000)
Fiscal Year 2005: ¥7,500,000 (Direct Cost: ¥7,500,000)
Fiscal Year 2004: ¥8,100,000 (Direct Cost: ¥8,100,000)
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| Keywords | cell migration / MIG-17 / ADAM family / fibulin / suppressor mutants / C.elegans / 変異体 |
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| Research Abstract |
1.Analysis of the fbl-1 gene
In C.elegans, an ADAM family metalloprotease MIG-17 is secreted from the body wall muscles and localizes to the gonadal basement membrane where it is required for directional migration of gonadal distal tip cells (DTCs). We found that dominant mutations in fibulin-1 (FBL-1), a Ca^<2+>-binding extracellular matrix protein, can suppress the DTC migration defects caused by loss of MIG-17 activity. Specific amino acid substitutions in the third EGF-like motif of one of the two isoforms, FBL-1C, which corresponds to mammalian fibulin-1C, suppress mig-17 mutations. It is known that fibulin-1 binds strongly with nidogen in vitro in mammals. Therefore, we analyzed the requirement of nidogen in the suppression of mig-17 mutants by fbl-1 gain-of-function mutations. The nidogen mutant nid-1 in C.elegans dose not exhibits gonadal migration defects. When we introduced nid-1 into mig-17 ; fbl-1 double mutants, the suppression effect of fbl-1 was totally cancelled and the triple mutants exhibited DTC migration defects similar to those in mig-17 single mutants. These results indicate that the mutant FBL-1 proteins suppress mig-17 mutant defects in a NID-1-dependent manner.
2.Analysis of the let-2 gene
The second suppressor locus, let-2, was found to encode the a2 chain of the basement membrane type IV collagen. We analyzed tissue distribution of LET-2 using specific antibodies and found that the mutant LET-2 proteins are secreted and localize to the gonadal basement membrane. The mutant LET-2 proteins may affect the structure or function of the gonadal basement membrane and thereby bypassing the requirement of MIG-17 in the control of DTC migration.
3.Isolation of new suppressor mutants
In this study, we isolated additional suppressors using EMS mutagenesis of mig-17 mutants. Twenty one independent mutants were isolated and they were assigned to at least 6 different loci.
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