敲减Wingless / Wnt1基因表达对赤拟谷盗发育中的影响

Wnt信号通路是进化中高度保守的一条信号转导途径，在调控动物的胚胎轴向正常发育、胚胎分化、决定细胞极性、维持成体动态平衡等方面发挥重要作用. 该信号通路的异常激活还与肿瘤的发生密切相关. 本实验将体外人工合成的Wingless(Wg)/Wnt1基因dsRNA显微注射入赤拟谷盗晚期幼虫体内，研究Wingless/Wnt1蛋白在赤拟谷盗发育过程中发挥的作用. 实验结果显示，注射 Wingless(wg)/Wnt1基因dsRNA后，赤拟谷盗发育形成的蛹，翅膀宽度减小，翅间距明显增大，且羽化过程也受到严重影响. 此外，qPCR结果表明，赤拟谷盗Wingless(Wg)/Wnt1基因被沉默后，Cadherin-like 和 Smoothened (Smo)基因的表达显著上调，Armadillo-2基因略上调. 这些结果揭示，Wnt-1 信号通路和赤拟谷盗翅膀发育以及成虫羽化过程密切相关. 蛹翅宽减小，翅间距增大，可能是由于调控细胞粘连及细胞形态的Cadherin-like 和Armadillo-2基因的上调所引起.更重要的是，Smo基因的上调，表明了Wnt信号通路和Hedgehog信号通路在赤拟谷盗发育过程中有交互作用.

Knocking-down of Wingless/Wnt1 Influences the Development of Tribolium castaneum

Known as highly conserved during evolution, the Wnt signaling pathway plays a vital role in regulating animal embryonic axis, embryonic differentiation, and deciding cell polarity and maintaining adult dynamic equilibrium. Mutations or deregulations of its components might cause the occurrence of carcinoma. We studied the role of Wingless/Wnt1 during larva-adult development of the red flour beetle, Tribolium castaneum, with dsRNA-mediated Wingless(Wg)/Wnt1 gene knocked down. The treated late larvae metamorphosed into pupae with drastically increased wing interval and decreased wing width (P<001). The pursuant pupa-adult eclosion was also severely affected and most of pupae died during this period. The qPCR result showed that the mRNA level of Cadherin-like and Smoothened (Smo) genes were up-regulated greatly, and that of armadillo-2 was slightly higher, after Wingless/Wnt1 gene was knocked down. We drew the conclusion that Wnt-1 signaling pathway is closely related to the proper wing development and adult metamorphosis of Tribolium. In addition, the elevated expression of Cadherin-like and Armadillo-2 may be accountable for the reduced wing width and enlarged wing interval caused by wg gene silencing, because those alterations can either enhance cell adhesion or change cell morphology. Importantly, the up-regulation of smo gene indicates that Hedgehog signaling pathway may be affected by the RNAi of Wg and involved in the abnormal or lethal phenotypes observed in our experiment.