Kang David S, Denlinger David L, Sim Cheolho
Department of Biology, Baylor University, Waco, TX 76798, USA.
Department of Evolution, Ecology, and Organismal Biology, Ohio State University, 318 West 12th Avenue, Columbus, OH 43210, USA; Department of Entomology, Ohio State University, 318 West 12th Avenue, Columbus, OH 43210, USA.
J Insect Physiol. 2014 May;64:48-53. doi: 10.1016/j.jinsphys.2014.03.005. Epub 2014 Mar 20.
The cessation of juvenile hormone (JH) production is a key endocrine event that halts ovarian development and hence initiates diapause in females of the mosquito, Culex pipiens. The shutdown in endocrine activity of the corpora allata (CA), the source of JH, was manifested in the smaller size of CA in females reared under short daylengths (diapause) compared to those reared under long daylengths (nondiapause), as well as in low expression of the mRNA encoding allatotropin, the neuropeptide that promotes JH biosynthesis in the CA. Genes encoding both allatotropin and allatostatin were identified in C. pipiens, but only expression levels of allatotropin differed in the two types of females. Knockdown of allatotropin mRNA using RNA interference in females programmed for nondiapause resulted in a cessation of ovarian development akin to diapause. This arrest in development could be reversed with an application of JH. Our results thus suggest that suppression of allatotropin is a critical link in regulating the shutdown of the CA during diapause.
保幼激素（JH）分泌的停止是一个关键的内分泌事件，它会停止卵巢发育，从而引发致倦库蚊雌蚊的滞育。作为JH来源的咽侧体（CA）内分泌活动的停止，表现为与在长日照（非滞育）条件下饲养的雌蚊相比，在短日照（滞育）条件下饲养的雌蚊的CA体积更小，以及编码促咽侧体素（一种促进CA中JH生物合成的神经肽）的mRNA表达水平较低。在致倦库蚊中鉴定出了编码促咽侧体素和咽侧体抑制素的基因，但只有促咽侧体素的表达水平在这两种类型的雌蚊中有所不同。在预定为非滞育的雌蚊中使用RNA干扰敲低促咽侧体素mRNA，导致卵巢发育停止，类似于滞育。这种发育停滞可以通过施用JH来逆转。因此，我们的结果表明，促咽侧体素的抑制是调节滞育期间CA关闭的关键环节。
