ABSTRACT

In Drosophila melanogaster, PD isoform of the double-stranded RNA binding protein (dsRBP) Loquacious (Loqs-PD) facilitates dsRNA cleavage to siRNA by Dicer-2. StaufenC (StauC) was discovered as a coleopteran-specific dsRBP required for dsRNA processing in coleopteran insects. Here, we show that StauC is essential for the high RNAi efficiency observed in coleopterans. Knockdown of StauC but not the homologs of Loqs-PD and R2D2 evoked a long-lasting insensitivity to RNAi in the coleopteran cell line, Ledp-SL1. The dsRNA insensitivity induced by StauC knockdown could not be overcome merely by an increase in dose or time of exposure to dsRNA or expression of Loquacious or R2D2. Furthermore, StauC but not Loqs and R2D2 are required for processing of dsRNA into siRNA. StauC overexpression also partly restored the impaired RNAi caused by the knockdown of Loqs-PD in D. melanogaster Kc cells. However, StauC was unable to compensate for the loss-of-the function of Dcr-2 or R2D2. Overall, these data suggest that StauC functions like Lops-PD in processing dsRNA to siRNA.

摘要

在黑腹果蝇, 双链 RNA 结合蛋白 (dsRBP) Loquacious (Loqs-PD) 的 PD 同种型促进 Dicer-2 将 dsRNA 切割成 siRNA。StaufenC (StauC) 被发现是鞘翅目昆虫中 dsRNA 加工所需的鞘翅目特异性 dsRBP。在这里，我们表明 StauC 对于在鞘翅目中观察到的高 RNAi 效率至关重要。敲除 StauC 而不是 Loqs-PD 和 R2D2 的同源物引起鞘翅目细胞系 Ledp-SL1 对 RNAi 的长期不敏感性。仅通过增加暴露于 dsRNA 的剂量或时间或 Loquacious 或 R2D2 的表达，无法克服由 StauC 敲低诱导的 dsRNA 不敏感性。此外，将 dsRNA 加工成 siRNA 需要 StauC 而不是 Loqs 和 R2D2。StauC 过表达也部分恢复了由 Loqs-PD 敲低引起的 RNAi 受损。D. 黑腹果蝇Kc 细胞。然而，StauC 无法弥补 Dcr-2 或 R2D2 的功能丧失。总体而言，这些数据表明，在将 dsRNA 加工成 siRNA 时，StauC 的功能类似于 Lops-PD。