Beyond the heat shock pathway: Heat stress responses in Drosophila development

Heat stress has broad effects on an organism and is an inevitable part of life. Embryos face a particular challenge when faced with heat stress - the intricate molecular processes that pattern the embryo can all be affected by heat, and the embryo lacks some of the strategies that adults can use to manage or avoid heat stress. We use Drosophila melanogaster as a model, as insects are capable of developing normally under a wide range of temperatures and are exposed to daily temperature swings as they develop. Research has focused on the heat shock pathway and the transcription of heat shock proteins as the main response to heat and heat damage. This review explores embryonic heat responses beyond the heat shock pathway. We examine the effects of heat from a biochemical standpoint, as well as highlighting other mechanisms of heat stress regulation, such as miRNA activity or other signaling pathways. We discuss how different elements of the heat stress response must be coordinated across the embryo to enable development under a wide range of temperatures. Studying heat stress in Drosophila melanogaster can be a powerful lens into how developmental systems ensure robustness to environmental factors.