| Budget Amount *help |
¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 2002: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2001: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2000: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Research Abstract |
The effects of high energy X-ray to White Leghorn embryos, or ^<252>Cf or 3 MeV neutron to mouse embryos on morphogenesis were studied. In order to check effects of radiation on neural crest cells, expression of a NT-3 gene was checked. Also, expression of a Pitx2 gene regarding to the right-left asymmetrical development was checked.
As the results, the right and left axis of a embryo was reversed by neutron irradiation. Decreasing of NT-3 gene expression by high energy X-ray was recognized. The degree of decreasing of gene expression was different in the embryos. Expression of the Pitx2 gene was also decreased after irradiation. Also, the cases that suggests mutation of the Pitx2 gene was recognized. It was indicated that expression of certain genes such as NT-3 were especially affected by radiation. Certain homeobox genes, however, were not mutated by radiation.
Besides, expression of genes regarding to the cell defense to radiation was studied. I examined effects of high energy X-ray to chicken embryos on expression of p53, ATM and RAD51. After 24 hr of 5 Gy or 8 Gy irradiation, expression of p53 and ATM gene was decreased significantly compared with controls. P53 and ATM are the important gene regarding to G_1 arrest and cell death by radiation irradiation, thus the results suggested that radiation affected cell defense system. Expression of RAD51 genes was increased to 2 times with controls after radiation irradiation. This result is different from a previous reports, thus, it is suggested that radiation irradiation activates DNA recombinant repair system.
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