Divergent transcriptional response to thermal stress by Anopheles gambiae larvae carrying alternative arrangements of inversion 2La
Divergent transcriptional response to thermal stress by Anopheles gambiae larvae carrying alternative arrangements of inversion 2La
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DOI：
10.1111/j.1365-294x.2011.05114.x
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发表时间：
2011-06-01
影响因子：
4.9
通讯作者：
Besansky, Nora J.
中科院分区：
文献类型：
--
作者：
Cassone, Bryan J.;Molloy, Matthew J.;Besansky, Nora J.
非洲疟疾蚊子冈比亚按蚊是多态性的染色体倒位2La，其频率强烈相关的干旱程度在整个环境梯度。最近的生理学研究表明，2La与成人的干燥和幼虫的热应激抗性，与其在干旱耐受性中的作用相一致。然而，这些特征的遗传基础仍然未知。为了鉴定可能参与对热应激的差异反应的基因，我们比较了热硬化2La或2L+a幼虫在三个时间点的全球基因表达谱，暴露于热应激后长达8小时。治疗和对照时间序列，重复四次，揭示了一个共同的和大规模的诱导的核心热休克基因，无论2La方向。然而，2La和2L+a安排之间的明显差异出现在最早（0.25小时）的时间点，在强度和性质的应激反应。总的来说，2La与更积极的反应有关：大量的基因是热反应和上调的。转录诱导的基因丰富的功能相关的泛素-蛋白酶体降解，伴侣和能量代谢。2L+a的更温和的转录反应在很大程度上是抑制性的，包括参与蛋白水解和能量代谢的基因。这些结果可能有助于解释2La倒位多态性在An中的维持。在冈比亚，由于在恶劣的气候条件下对热的高度敏感性所带来的生存益处，可能会被在较稳定的气候条件下作出如此剧烈反应的代谢代价所抵消。
The African malaria mosquito Anopheles gambiae is polymorphic for chromosomal inversion 2La, whose frequency strongly correlates with degree of aridity across environmental gradients. Recent physiological studies have associated 2La with resistance to desiccation in adults and thermal stress in larvae, consistent with its proposed role in aridity tolerance. However, the genetic basis of these traits remains unknown. To identify genes that could be involved in the differential response to thermal stress, we compared global gene expression profiles of heat-hardened 2La or 2L+a larvae at three time points, for up to eight hours following exposure to the heat stress. Treatment and control time series, replicated four times, revealed a common and massive induction of a core set of heat-shock genes regardless of 2La orientation. However, clear differences between the 2La and 2L+a arrangements emerged at the earliest (0.25 h) time point, in the intensity and nature of the stress response. Overall, 2La was associated with the more aggressive response: larger numbers of genes were heat responsive and up-regulated. Transcriptionally induced genes were enriched for functions related to ubiquitin-proteasomal degradation, chaperoning and energy metabolism. The more muted transcriptional response of 2L+a was largely repressive, including genes involved in proteolysis and energy metabolism. These results may help explain the maintenance of the 2La inversion polymorphism in An. gambiae, as the survival benefits offered by high thermal sensitivity in harsh climates could be offset by the metabolic costs of such a drastic response in more equable climates.