Developmental profile of annexin IX and its possible role in programmed cell death of the Bombyx mori anterior silk gland
Developmental profile of annexin IX and its possible role in programmed cell death of the Bombyx mori anterior silk gland
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DOI：
10.2108/zsj.23.533
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发表时间：
2006-06-01
影响因子：
0.9
通讯作者：
Sakurai, Sho
中科院分区：
文献类型：
--
作者：
Kaneko, Yu;Takaki, Keiko;Sakurai, Sho
在蛹变态过程中，家蚕（Bombyx mori）的前丝腺（ASG）会经历由 20-羟基蜕皮激素（20E）触发的程序性细胞死亡（PCD）。膜联蛋白 IX (ANX IX) 已被鉴定为垂死 ASG 中的 20E 诱导基因，我们在此表明其表达在注定死亡的组织中下调，但在蛹变态存活的组织中则不然。在进食期间，当蜕皮类固醇滴度较低时，ANX IX 的表达在 ASG 中较高，并且随着蜕皮类固醇滴度的上升而触发蛹变态，ANX IX 的表达会降低。在肠道净化之前，将 ASG 体外暴露于与肠道净化时存在的蜕皮类固醇浓度相对应的 20E 水平，导致 ANX IX 信使 RNA 水平下降。 EcR 和 USP 的表达谱以及这些基因的 20E 浓度响应表明 EcR-A 和 EcR-B1 同工型的相对丰度在 ANX IX 调节中的重要性。这些结果表明 ANX IX 通过延迟或抑制对预蛹期血淋巴蜕皮类固醇浓度增加的反应来参与 PCD 时间的确定。
During pupal metamorphosis, the anterior silk gland (ASG) of the silkworm, Bombyx mori, undergoes programmed cell death (PCD), which is triggered by 20-hydroxyecdysone (20E). Annexin IX, (ANX IX) has been identified as a 20E-inducible gene in dying ASGs, and we show here that its expression is down-regulated in tissues destined to die but not in tissues that survive pupal metamorphosis. ANX IX expression was high in the ASGs during the feeding period, when the ecdysteroid titer was low, and decreased in response to the rising ecdysteroid titer that triggered pupal metamorphosis. Before gut purge, in vitro exposure of the ASGs to 20E levels corresponding to the ecdysteroid concentration present at the time of gut purge caused a decrease in ANX IX messenger RNA levels. Expression profiles of EcR and USP, and the 20E concentration-responses of these genes, indicate the importance of the relative abundance of EcR-A and EcR-B1 isoforms in ANX IX regulation. These results suggest an involvement of ANX IX in the determination of PCD timing by delaying or suppressing the response to the increase in hemolymph ecdysteroid concentration during the prepupal period.