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Programmed cell death during the adult midline formation in Drosophila melanogaster

果蝇成虫中线形成过程中的程序性细胞死亡

基本信息

批准号：
10640644
负责人：
KIMURA Ken-ichi
金额：
$ 1.15万
依托单位：
Hokkaido University of Education
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640644/
关键词：
Drosophila melanogaster Programmed cell death morphogenesis apoptosis metamorphosis

项目摘要

In Drosophila melanogaster, a midline formation for adult epidermis proceed during metamorphosis. I examined the involvement of the cell death during the midline formation.A replacement of epidermis from larval cells to adult ones was examined at the abdominal region during metamorphosis. The larval epidermal cells migrated from dorsal to midline and were detached from the cuticle at the midline between 24 to 36 hr APF. In vivo observation of the elimination process of the larval cells, using the gal4/UAS-GFP system, showed that the nucleus of the larval cells was fragmented and that the apoptotic bodies appeared. Thus, the larval epidermal cells would die through the apoptotic processes. The ectopic expression of anti-apoptotic gene, p35, whose products inhibit the activity of the caspases that proceed the apoptosis, in the larval epidermal cells during metamorphosis prevented the death of them and caused an adult fly having the larval epidermis at the midline. In the hid mutants, inhibition of cell death occurred in the larval epidermal cells, which also caused the defect in the adult midline. Thus, cell death in the larval epidermal cells is necessary for the midline formation.At the thoracic region, adult epidermal cells fuse to make midline during early pupa. Our studies using TUNEL staining showed that some cells at the midline die in this process. In the reaper-lacZ flies, the expression of marker gene was observed at the midline. Also, at the same region, I found that the dpp gene was expressed. To examine whether the dpp signal controls the expression of reaper gene. I analyzed the effect of mutation of dpp-related genes on the expression of reaper. However, the reaper expression was not changed in the mutants, suggesting other factor that control the cell death during the midline formation.

在果蝇中，成体表皮的中线形成在变态过程中进行。在中线形成的过程中，我观察到了细胞死亡的参与。在变态过程中，在腹部区域，观察到了表皮从幼虫细胞到成虫细胞的替换。幼虫的表皮细胞从背侧向中线迁移，并在24 ~ 36小时的APF期间从中线的角质层上脱落。利用gal 4/UAS-GFP系统在体内观察幼虫细胞的消除过程，显示幼虫细胞的细胞核碎裂，并出现凋亡小体。因此，幼虫表皮细胞将通过凋亡过程死亡。在变态过程中，抗凋亡基因p35在幼虫表皮细胞中异位表达，其产物抑制进行凋亡的半胱氨酸天冬氨酸蛋白酶的活性，从而阻止了它们的死亡，并导致成虫具有中线的幼虫表皮。在hid突变体中，幼虫表皮细胞的细胞死亡受到抑制，这也导致了成虫中线的缺陷。因此，幼虫表皮细胞的死亡是中线形成的必要条件。在胸区，成虫表皮细胞在蛹早期融合形成中线。我们用TUNEL染色的研究表明，在这个过程中，中线的一些细胞死亡。在reaper-lacZ果蝇中，标记基因的表达位于中线。而且，在同一区域，我发现dpp基因表达。检测dpp信号是否调控reaper基因的表达。分析了dpp相关基因突变对reaper表达的影响。然而，在突变体中reaper的表达没有改变，这表明在中线形成期间控制细胞死亡的其他因素。