Bowen I D, Morgan S M, Mullarkey K
School of Pure and Applied Biology, University of Wales College of Cardiff.
Cell Biol Int. 1993 Jan;17(1):13-33. doi: 10.1006/cbir.1993.1002.
The salivary gland cells of Calliphora vomitoria larvae initiate and complete their own destruction in a programmed manner at the onset of metamorphosis. On entering the post-feeding period the larvae come to rest and the polytene salivary gland cells show a significant increase in DNA synthesis followed closely by a surge of mRNA synthesis accompanied by increasing protein production. During this prelude to cell death the new mRNA gives rise to at least 10 new proteins. The first new proteins having a MWt between 30 and 100kD appear by day 8 of the life-cycle and a number persist until the advent of cell death on day 9. Other new proteins appear in a cascade of production during day 8 and in vitro translation of mRNA produced at this time shows a new 55kD protein appearing before cell destruction. Significantly no evidence of DNA degeneration or laddering associated with classical apoptosis was observed, on the contrary considerable DNA synthesis in the form of chromosomal endoduplication or "genomic amplification" was seen; selective gene expression being apparently controlled at translational level. Overall the results strongly suggest a synthetically mediated programmed cell death in the metamorphosing salivary glands of the blow-fly which is distinct from apoptosis.
红头丽蝇幼虫的唾液腺细胞在变态开始时以程序性方式启动并完成自身破坏。进入取食后期后，幼虫静止下来，多线唾液腺细胞的DNA合成显著增加，紧接着mRNA合成激增，同时蛋白质产量增加。在细胞死亡的这个前奏阶段，新的mRNA产生至少10种新蛋白质。第一种分子量在30至100kD之间的新蛋白质在生命周期的第8天出现，一些蛋白质一直持续到第9天细胞死亡之时。其他新蛋白质在第8天以一连串的方式产生，此时产生的mRNA的体外翻译显示一种新的55kD蛋白质在细胞破坏之前出现。值得注意的是，未观察到与经典细胞凋亡相关的DNA降解或梯状条带的证据，相反，看到了以染色体核内复制或“基因组扩增”形式存在的大量DNA合成；选择性基因表达显然在翻译水平受到控制。总体而言，结果强烈表明，在丽蝇变态的唾液腺中存在一种由合成介导的程序性细胞死亡，它与细胞凋亡不同。
