1992 Fiscal Year Final Research Report Summary
Programmed cell death-The molecular mechanism of tail regression during amphibian metamorphosis
| Project/Area Number |
03670134
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
General medical chemistry
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| Research Institution | TOKYO METROPOLITAN INSTITUTE FOR NEUROSCIENCES |
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Principal Investigator |
YAOITA Yoshio Tokyo Metropolitan Institute for Neuroscience, Department of Neurobiology, Staff Scientist, 分子神経生物学研究部門, 副参事研究員 (00166472)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Programmed Cell Death / Metamorphosis / Xenopus / Developmental Biology / Genetic Engineering |
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| Research Abstract |
In order to study the molecular mechanism of tail resorption, I tried to establish the method of subtraction library using RNase H specificity and polymerase chain reaction, clone metamorphosis-specific genes expressed in regressing tail and obtain cell lines derived from tadpole tail for the functional assay. A small amount of regressing tail mRNA was hybridized to a large amount of tail cDNA from stage 57 tadpole before the climax and this mixture was treated by RNase H to digest the mRNA hybridized with cDNA. The cDNA synthesized from the resistant mRNA was amplified by PCR, inserted into plasmid and screened by the +/- method. 36 independently isolated clones fell into 10 different genes and were divided into 3 groups which show different expression patterns among tissues. The first group of genes are expressed in all tissues including brain, eye, hind limb and tail. The second one is activated in hind limb and tail. The third group are transcribed in only tail.
A myoblastic cell line from tadpole tail is maintained more than one and half years and the cells die upon addition of 10 nM of thyroid hormone(T_3) which is a physiological level in plasma during metamorphosis. Only one gene, T6-5-12, is activated in these cells treated by thyroid hormone within one day. The expression of thyroid hormone receptor beta mRNA is induced 4 hours after T_3 treatment, whereas thyroid hormone receptor alpha is expressed constantly. The expression of T6-5-12 is observed 8 hours after the treatment. It is possible that thyroid hormone receptor alpha binds to T_3 at first, this complex activates thyroid hormone receptor beta gene, and finally the expression of T6-5-12 is induced by the compound of these receptors and thyroid hormone.
By introducing specific genes of regressing tail into the myoblastic cells, the molecular mechanism of tail absorption during amphibian metamorphosis (programmed cell death) will be elucidated in the near future.
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Research Products
(6 results)
