Shen Jie, Curtis Christina, Tavaré Simon, Tower John
Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA.
Aging (Albany NY). 2009 Jan 30;1(2):191-211. doi: 10.18632/aging.100018.
Conditional expression of transgenes in Drosophila was produced using the Geneswitch system, wherein feeding the drug RU486/Mifepristone activates the artificial transcription factor Geneswitch. Geneswitch was expressed using the Actin5C promoter and this was found to yield conditional, tissue-general expression of a target transgene (UAS-GFP) in both larvae and adult flies. Nervous system-specific (Elav-GS) and fat body-specific Geneswitch drivers were also characterized using UAS-GFP. Fourteen genes implicated in growth, apoptosis and senescence regulatory pathways were over-expressed in adult flies or during larval development, and assayed for effects on adult fly life span. Over-expression of a dominant p53 allele (p53-259H) in adult flies using the ubiquitous driver produced increased life span in females but not males, consistent with previous studies. Both wingless and Ras activated form transgenes were lethal when expressed in larvae, and reduced life span when expressed in adults, consistent with results from other model systems indicating that the wingless and Ras pathways can promote senescence. Over-expression of the caspase inhibitor baculovirus p35 during larval development reduced the mean life span of male and female adults, and also produced a subset of females with increased life span. These experiments suggest that baculovirus p35 and the wingless and Ras pathways can have sex-specific and developmental stage-specific effects on adult Drosophila life span, and these reagents should be useful for the further analysis of the role of these conserved pathways in aging.
利用基因开关系统在果蝇中实现转基因的条件性表达，其中喂食药物RU486/米非司酮可激活人工转录因子基因开关。基因开关由肌动蛋白5C启动子表达，结果发现其能在幼虫和成虫中产生目标转基因（UAS-GFP）的条件性、组织普遍表达。还使用UAS-GFP对神经系统特异性（Elav-GS）和脂肪体特异性基因开关驱动子进行了表征。在成年果蝇或幼虫发育期间，对14个与生长、凋亡和衰老调控途径相关的基因进行了过表达，并检测其对成年果蝇寿命的影响。使用普遍存在的驱动子在成年果蝇中过表达显性p53等位基因（p53-259H），结果显示雌性果蝇寿命延长，而雄性果蝇寿命未延长，这与之前的研究结果一致。无翅基因和Ras激活形式的转基因在幼虫中表达时具有致死性，在成虫中表达时会缩短寿命，这与其他模型系统的结果一致，表明无翅基因和Ras途径可促进衰老。在幼虫发育期间过表达半胱天冬酶抑制剂杆状病毒p35可缩短成年雌雄果蝇的平均寿命，同时也产生了一部分寿命延长的雌性果蝇。这些实验表明，杆状病毒p35以及无翅基因和Ras途径对成年果蝇寿命可产生性别特异性和发育阶段特异性影响，这些试剂应有助于进一步分析这些保守途径在衰老中的作用。
