Bali Arundhati, Shravage Bhupendra V
Developmental Biology Group, MACS-Agharkar Research Institute, Pune, India.
Int J Dev Biol. 2017;61(8-9):551-555. doi: 10.1387/ijdb.170077bs.
Autophagy is an evolutionarily conserved process which is upregulated under various stress conditions, including nutrient stress and oxidative stress. Amongst autophagy related genes (Atgs), Atg8a (LC3 in mammals) is induced several-fold during nutrient limitation in Drosophila. The minimal Atg8a cis-regulatory module (CRM) which mediates transcriptional upregulation under various stress conditions is not known. Here, we describe the generation and analyses of a series of Atg8a promoter deletions which drive the expression of an mCherry-Atg8a fusion cassette. Expression studies revealed that a 200 bp region of Atg8a is sufficient to drive expression of Atg8a in nutrient rich conditions in fat body and ovaries, as well as under nutrient deficient conditions in the fat body. Furthermore, this 200 bp region can mediate Atg8a upregulation during developmental histolysis of the larval fat body and under oxidative stress conditions induced by HO. Finally, the expression levels of Atg8a from this promoter are sufficient to rescue the lethality of the Atg8a mutant. The 200 bp promoter-fusion reporter provides a valuable tool which can be used in genetic screens to identify transcriptional and post-transcriptional regulators of Atg8a.
自噬是一个进化上保守的过程，在包括营养应激和氧化应激在内的各种应激条件下会被上调。在自噬相关基因（Atgs）中，Atg8a（哺乳动物中的LC3）在果蝇营养限制期间会被诱导增加数倍。介导各种应激条件下转录上调的最小Atg8a顺式调控模块（CRM）尚不清楚。在这里，我们描述了一系列驱动mCherry-Atg8a融合盒表达的Atg8a启动子缺失的产生和分析。表达研究表明，Atg8a的一个200 bp区域足以在富含营养的条件下驱动脂肪体和卵巢中Atg8a的表达，以及在脂肪体营养缺乏条件下驱动其表达。此外，这个200 bp区域可以在幼虫脂肪体的发育性组织溶解过程中以及在HO诱导的氧化应激条件下介导Atg8a的上调。最后，来自该启动子的Atg8a表达水平足以挽救Atg8a突变体的致死性。这个200 bp启动子融合报告基因提供了一个有价值的工具，可用于遗传筛选以鉴定Atg8a的转录和转录后调节因子。
