Characterization of hypoxia-inducible factor α and its response to hypoxia in Callosobruchus chinensis (Coleoptera, Bruchidae)

Hypoxia-inducible factor (HIF) plays an essential role in hypoxic
adaptation in various organisms. Callosobruchus chinensis, a common food
storage pest, is highly adapted to hypoxic conditions, while the
underlying mechanism of which is currently unclear. Here, we isolated,
sequenced, and bioinformatically analyzed HIF1α from C. chinensis, then
examined its mRNA and protein expression profiles under hypoxic conditions
for various developmental stages and tissue types. The effects of
environmental hypoxia on other genes in the HIF pathway response,
aspartyl-hydroxylase (FIH) and prolyl hydroxylase (PHD), were also
examined. We found that FIH and PHD were also highly conserved and that
their expression varied with developmental stage, tissue type, and
environmental hypoxia. Overall, hypoxia caused an increase in HIF1α and
FIH mRNA expression, and a decrease in PHD mRNA expression, while
expression of their proteins showed different in response to hypoxia.
HIF1α protein levels increased, PHD and FIH protein levels decreased under
hypoxic conditions, compared to normoxic conditions. This study has
preliminarily investigated the bioinformation of C. chinensis HIF1α
response relationship between HIF1α and its hydroxylases under normoxic
and hypoxic conditions, which might provide important clues for future
work on clarifying the mechanism of stored-product insect unique hypoxia
adaption.

缺氧诱导因子（Hypoxia-inducible factor, HIF）在各类生物的低氧适应过程中发挥关键作用。绿豆象（Callosobruchus chinensis）作为常见的储粮害虫，对低氧环境具有极强的适应性，但其潜在机制目前尚不明确。本研究从绿豆象中分离、测序并通过生物信息学分析了HIF1α，随后检测了其在不同发育阶段和组织类型中低氧条件下的mRNA及蛋白表达谱。此外，本研究还探究了环境低氧对HIF通路中其他响应基因——天冬氨酰羟化酶（FIH）和脯氨酰羟化酶（PHD）的影响。研究发现，FIH和PHD同样高度保守，且其表达水平随发育阶段、组织类型及环境低氧状态的不同而变化。总体而言，低氧导致HIF1α和FIH的mRNA表达水平升高，PHD的mRNA表达水平降低，而三者的蛋白表达对低氧的响应模式存在差异。与常氧条件相比，低氧条件下HIF1α蛋白水平升高，PHD和FIH蛋白水平降低。本研究初步探究了绿豆象HIF1α的生物信息特征，以及常氧与低氧条件下HIF1α与其羟化酶之间的响应关系，这或将为后续阐明储粮昆虫独特低氧适应机制的研究提供重要线索。