Department of Biology, The University of Western Ontario, London, ON, Canada.
Insect Mol Biol. 2013 Oct;22(5):541-50. doi: 10.1111/imb.12044. Epub 2013 Jul 31.
Frost (Fst) is a candidate gene associated with the response to cold in Drosophila melanogaster because Fst mRNA accumulation increases during recovery from low temperature exposure. We investigated the contribution of Fst expression to chill-coma recovery time, acute cold tolerance and rapid cold hardening (RCH) in adult D. melanogaster by knocking down Fst mRNA expression using GAL4/UAS-mediated RNA interference. In this experiment, four UAS-Fst and one tubulin-GAL4 lines were used. We predicted that if Fst is essential for cold tolerance phenotypes, flies with low Fst mRNA levels should be less cold tolerant than flies with normal levels of cold-induced Fst mRNA. Cold-induced Fst abundance and recovery time from chill-coma were not negatively correlated in male or female flies. Survival of 2 h exposures to sub-zero temperatures in Fst knockdown lines was not lower than that in a control line. Moreover, a low temperature pretreatment increased survival of severe cold exposure in flies regardless of Fst abundance level during recovery from cold stress, suggesting that Fst expression is not essential for RCH. Thus, cold-induced Fst accumulation is not essential for cold tolerance measured as chill-coma recovery time, survival to acute cold stress and RCH response in adult D. melanogaster.
弗罗斯特（Fst）是与黑腹果蝇对低温反应相关的候选基因，因为 Fst mRNA 的积累在从低温暴露中恢复时增加。我们通过 GAL4/UAS 介导的 RNA 干扰降低 Fst mRNA 表达来研究 Fst 表达对成体 D. melanogaster 冷休克恢复时间、急性耐寒性和快速冷驯化（RCH）的贡献。在这个实验中，使用了四个 UAS-Fst 和一个 tubulin-GAL4 品系。我们预测如果 Fst 对耐寒表型至关重要，那么 Fst mRNA 水平低的果蝇应该比 Fst mRNA 正常诱导的果蝇耐寒性差。在雄性或雌性果蝇中，冷诱导的 Fst 丰度与冷休克恢复时间之间没有负相关。在 Fst 敲低系中，2 小时暴露于亚零温度下的存活率并不低于对照系。此外，低温预处理增加了冷应激恢复过程中无论 Fst 丰度水平如何，严重冷暴露的存活率，表明 Fst 表达对于 RCH 并非必需。因此，冷诱导的 Fst 积累对于黑腹果蝇成体的冷休克恢复时间、急性耐寒性和 RCH 反应的耐寒性测量并不是必需的。
