| Project/Area Number |
04640659
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
動物発生・生理学
|
|---|
| Research Institution | HIROSHIMA UNIVERSITY |
|---|
Principal Investigator |
KAWAHARA Akira Hiroshima Univ., Fac.of Integ.Arts & Sci, Associate Prof., 総合科学部, 助教授 (50112157)
|
|---|
| Project Period (FY) |
1992 – 1993
|
| Project Status |
Completed (Fiscal Year 1993)
|
| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1993: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1992: ¥1,400,000 (Direct Cost: ¥1,400,000)
|
|---|
| Keywords | Metamorphosis / Thyroid hormone / Xenopus laevis / Hepatocyte / Gene expression |
|---|
| Research Abstract |
Metamorphic changes in the amphibian liver are initiated by thyroid hormone action and the pattern of gene expression in larval cells is reprogramd to that of adult cells. In order to elucidate molecular mechanism involved in this reprograming process, the research project presented here aimed to isolate and characterize cDNAs whose expressions were regulated metamorphically.
The two cDNA libraries were constructed from liver mRNAs of the animals at the prometamorphic and the climax stages, respectively. Furthermore, the prometamorphic-cDNAs were subtracted from the climax-cDNAs and a library of cDNAs enriched in metamorphically induced sequenses was also constructed. From this substructed cDNA library, many metamorphically induced cDNA clones were isolated by differential hybridization screening method. Northern hybridization analysis represented that there were three types of mRNA accumulation pattern, namely some mRNAs initiate to increase at prometamorphic stage, the others at climax stage, and one (M3cDNA) transiently increase at metamorphic climax stage. Treatment of premetamorphic larva with thyroid hormone could induce the expression of the cognate genes with two different time lags (several hr and longer than 24 hr). M3 mRNA was observed only in liver parenchymal cells during metamorphic climax stages. furthermore, thyroid hormone could not induce the expression of M3 gene in the primary cultured adult hepatocytes. The sequense analysis of M3 cDNA represented that there was no related genes at present.
|
