2005 Fiscal Year Final Research Report Summary
Mechanism of Region-dependent Metamorphic Tissue Remodeling
| Project/Area Number |
15370028
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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 |
Morphology/Structure
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
YOSHIZATO Katsutoshi Hiroshima University, Graduate School of Science, Professor, 大学院・理学研究科, 教授 (20095516)
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| Co-Investigator(Kenkyū-buntansha) |
KASHIWAGI Akihiko Hiroshima University, Graduate School of Science, Professor, 大学院・理学研究科, 教授 (50106796)
SUZUKI Kenichi Hiroshima University, Graduate School of Science, Assistant, 大学院・理学研究科, 助手 (90363043)
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| Project Period (FY) |
2003 – 2005
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| Keywords | metamorphosis / thyroid hormone / Hox genes / skin / mircro array / thyroid hormone response element / tissue remodeling / transgenesis |
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| Research Abstract |
(1)Development of a method to yield conditional transgenic tadpoles usable for researches on anuran metamorphosis. An expression gene construct was made, whose expression was inducible by tetracycline. When transfected into Xenopus tadpole skin, the gene in the construct was expressed in an tetracycline-dependent manner. However, germ line-transgenic tadpoles bearing this construct failed to express it when exposed to the hormone, although a report had been published that it was inducible by the reagent. We consider that a further technical improvement is required for stable and reproducible expressions. (2)Regulation of expression of genes that control the region-dependent metamorphic remodeling of larval skin. We had reported that a PDGF/PDGFR signaling plays a key role in the region-dependent skin remodeling of tadpoles and thought that genes associated with the signaling are under the control of Hox genes. We obtained a few lines of experimental evidence that supported this hypothe
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sis. (1)Hoxa 13 mRNA was exclusively expressed in the tail spinal cord. (2)An enforced expression of Hoxa 13 in the tail spinal cord resulted in the acceleration of apoptosis in the presence of thyroid hormone (TH). However, the acceleration did not take place with its dominant negative form.
(3)Comprehensive analysis of genes associated with the region-dependent skin remodeling. We made an oligo-microarray test against total RNAs from larval skins treated with TH and identified 1,497 and 962 genes whode expressions were up- and down-regulated by TH, respectively. There were approximately 500 TH-early responsive genes whose expression levels were changeable within 24 hours after TH treatment. In silico analyses for the presence of the thyroid hormone response element (TRE) were performed against these early response genes using genomic sequence databases of Xenopus tropicalis. As a result, 20 genes were identified that contained TRE. Xak-C gene was one of such genes and the gel shift assay indicated that its TRE was functional. A few genes whose expressions were regulated by TH were characterized further in terms of expression profiles during metamorphosis. Less
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Research Products
(5 results)
