Murata Yasumasa, Osakabe Masahiro
Laboratory of Ecological Information, Graduate School of Agriculture, Kyoto University, Japan.
Environ Entomol. 2017 Dec 8;46(6):1448-1455. doi: 10.1093/ee/nvx169.
Exposure to ambient ultraviolet-B (UVB) radiation generates DNA lesions, such as cyclobutane pyrimidine dimers and 6-4 pyrimidine-pyrimidine photoproducts in Tetranychus urticae Koch (Acari: Tetranychidae). Larvae appeared normal and healthy after UVB irradiation. Conversely, many mites were trapped in their old epidermis or experienced retarded development and shrunk, thus failing to molt from protochrysalises to protonymphs and died. This suggested that DNA lesions per se were not causing lethality in mites unless damaged genes were expressed. UVB-induced DNA lesions may have interfered with DNA replication and gene expression during the physiological changes of morphogenesis in the chrysalis stage. Comprehensive gene expression analysis by RNA sequencing revealed that gene expression involving epidermal tissue (characteristically cuticular protein genes) and myosin heavy chain muscle-like genes were downregulated in protochrysalises irradiated with UVB at the larval stage. We conclude that the success of protochrysalis molting is determined by whether the DNA lesions of genes, particularly those connected with morphogenesis, are repaired before expression at the protochrysalis stage.
暴露于环境中的紫外线B（UVB）辐射会在二斑叶螨（叶螨科：叶螨属）中产生DNA损伤，如环丁烷嘧啶二聚体和6-4嘧啶-嘧啶光产物。UVB照射后，幼虫看起来正常且健康。相反，许多螨被困在它们的旧表皮中，或发育迟缓并萎缩，因此无法从原蛹蜕皮为若螨并死亡。这表明DNA损伤本身并不会导致螨死亡，除非受损基因被表达。UVB诱导的DNA损伤可能在蛹期形态发生的生理变化过程中干扰了DNA复制和基因表达。通过RNA测序进行的综合基因表达分析表明，在幼虫期接受UVB照射的原蛹中，涉及表皮组织（典型的表皮蛋白基因）和肌球蛋白重链肌肉样基因的基因表达下调。我们得出结论，原蛹蜕皮的成功与否取决于基因的DNA损伤，特别是那些与形态发生相关的损伤，在原蛹期表达之前是否得到修复。
