Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi, Uttar Pradesh 221 005, India.
Eur J Cell Biol. 2011 Jan;90(1):72-80. doi: 10.1016/j.ejcb.2010.08.010. Epub 2010 Oct 30.
Drosophila development proceeds through three larval stages, before it pupates to reach adulthood. During pupation, larval tissues are destructed by programmed cell death and replaced by adult structures. Programmed cell death is a tightly regulated process accomplished by the induction of three closely linked pro-apoptotic genes reaper, hid and grim, ultimately leading to the activation of caspases, DRONC and DRICE and results in cell death. Unlike other larval tissues, Malpighian tubules are unique in not undergoing characteristic ecdysone-induced apoptosis and are carried to the adults. In this paper we show that apoptotic proteins, HID, GRIM, DRONC and DRICE are expressed in the Malpighian tubules, however they are sequestered in the nucleus. Significantly DRONC and DRICE are not enzymatically processed to active forms in the Malpighian tubules, however, ectopic expression of pro-apoptotic proteins leads to malformed Malpighian tubules and lethality. We also show that the Drosophila inhibitor of apoptotic protein 1, DIAP1, is localized and processed differently in Malpighian tubules. These results provide first evidence in favor of differential activity of apoptotic proteins in Malpighian tubules.
果蝇的发育经过三个幼虫阶段，然后化蛹达到成虫。在化蛹过程中，幼虫组织通过程序性细胞死亡被破坏，并被成虫结构取代。程序性细胞死亡是一个由三个紧密相连的促凋亡基因 reaper、hid 和 grim 的诱导来完成的严格调控过程，最终导致 caspase、DRONC 和 DRICE 的激活，导致细胞死亡。与其他幼虫组织不同，马氏管的独特之处在于不经历典型的蜕皮激素诱导的细胞凋亡，并被带到成虫。在本文中，我们表明凋亡蛋白 HID、GRIM、DRONC 和 DRICE 在马氏管中表达，但它们被隔离在细胞核中。重要的是，DRONC 和 DRICE 没有在马氏管中被酶切为活性形式，然而，促凋亡蛋白的异位表达导致马氏管畸形和致死。我们还表明，果蝇凋亡抑制蛋白 1（DIAP1）在马氏管中的定位和加工方式不同。这些结果首次提供了支持凋亡蛋白在马氏管中具有不同活性的证据。
