1999 Fiscal Year Final Research Report Summary
Hormonal control of pupal commitment and programmed cell death
| Project/Area Number |
09440273
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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 |
生物形態・構造
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| Research Institution | Kanazawa University |
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Principal Investigator |
SAKURAI Sho Department of biology, Kanazawa University, Professor, 理学部, 教授 (80143874)
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| Co-Investigator(Kenkyū-buntansha) |
IWAMI Masafumi Department of biology, Kanazawa University, Associate P., 理学部, 助教授 (40193768)
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| Project Period (FY) |
1997 – 1999
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| Keywords | ecdysone / juvenile hormone / determination / apoptosis / anterior silk gland / forewing disc / 翅成虫原基 |
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| Research Abstract |
Present research determined and showed the followings during the propqsed period.
(1) Hormone titer : Hemolymph juvenile hormone and ecdysteroid titers were determined every 12 h for JH during a period from third stadium to pupation and every 2 h for ecdysteroids from 4th stadium through pupation.
(2) Pupal commitment of for wing discs : The change in commitment in wing discs was found to be finished for 16 h after last larval ecdysis. 20-Hydroxyecdyosne did not accelerate the rate of the change and JH failed to suppress the change at a physiological dose. JH also did not affect the change in commitment by. 20E. The change in commitment may be initiated at the time of head capsule slippage (HCS). After HCS, the discs became responsive dramatically to 20E while lost their responsiveness to JH. The discs of early 4th stadium, that were not pupally committed by 20E in vitro, were able to be pupally committed by two step incubation, first with no hormone followed by 20E challenge. In such conditions, the discs were pupally committed and the commitment was strongly suppressed by JH at a concentration lower than physiological one.
(3) Programmed cell death of anterior silk gland : Apoptosis of anterior silk gland is induced by 20E in vitro. After 20E challenge, gene expression and protein synthesis necessary for the death were completed within 8 and 18 h, respectively. Nevertheless, 20E must be present for 42 h for completion of the death. Along with other evidence, 20E was suggested to act after 18 h through a membrane-bound receptor and the second messenger is cyclic AMP. Seven early genes have been cloned and five of them exhibited homology of known genes in other animals but two did not possess open reading frame. Analysis of their function is under progress.
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