| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1987: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1986: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Research Abstract |
The homozygous embryo of the pnd mutant of Bombyx silkworm never enters diapause,owing to genetic defect of a pnd^+ gene,but the embryonic defect caused by the pnd mutation is repairable after fertilization by the action of the paternal pnd^+ gene. Present studies were designed (1) to define the effect of the pnd^+ gene on the initiation of diapause metabolism, (2) to purify the pnd^+ genespecific protein,and (3) to examine the mode of action of the pnd^+ gene.
(1) We demonstrated that the pnd^+ gene controls diapause metabolism,such as the decrease in oxygen consumption,the decrease in DNA synthesis and the decrease in protein synthesis.
(2) Using two-dimensional gel electrophoresis,a putative pnd^+ gene-specific protein was identified in the heterozygote. It was demonstrated that the timing of appearacnce of the protein precedes by about 3 hr the stage where oxygen consumption decreases,and the protein is basic and has a molecular weight of approx.22,000. The pnd^+ protein was partially purified by means of the HPLC using first a TSKSP-5PW column and next TSK-G30000SW column.We are now trying to prepare a monoclonal antibody for the protein.
(3) It has been proposed that an oxygen barrier is formed in the chorion at the time of diapause initiation,and the pnd^+ gene may participate the formation.Thus oxygen permeability of the chorion was measured by an apparatus especially designed for this purpose.We demonstrated that oxygen permeability dose not change appreciably during diapause initiation.This result suggests that the pnd^+ gene is not involved in the mechanism which determines oxygen permeability of the chorion.
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