Maternal provision of transformer-2 is required for female development and embryo viability in the wasp Nasonia vitripennis
Maternal provision of transformer-2 is required for female development and embryo viability in the wasp Nasonia vitripennis
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DOI：
10.1016/j.ibmb.2017.09.007
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发表时间：
2017-11-01
影响因子：
3.8
通讯作者：
Verhulst, Eveline C.
中科院分区：
文献类型：
--
作者：
Geuverink, Elzemiek;Rensink, Anna H.;Verhulst, Eveline C.
在昆虫性别决定中，一个主要的信号启动了遗传性别决定级联，在大多数昆虫目中，该级联随后被转换器(TrA)直系同源基因向下传递。只有雌性特异剪接的tra mRNA才能产生功能性的TRA蛋白，该蛋白与TRA2形成一个由Transformer-2(Tra2)同源基因编码的复合体，作为下游转录因子Doublesex(Dsx)和less(Fru)的性别特异性剪接调节因子。在这里，我们鉴定了单倍体寄生黄蜂NV-TRA2(NV-TRA2)的Tra2同源基因，并确认了它在NV-TRA2性别决定中的作用。通过亲本RNA干扰(PRNAi)敲除NV-Tra2，导致二倍体后代从雌性到雄性的完全性别逆转，表明NV-Tra2对雌性性别决定是必需的。由于NV-Tra2 pRNAi导致早期发育阶段的频繁死亡，在胚胎发育过程中，母体提供NV-Tra2转录本显然也是另一种非性别决定功能所必需的。此外，NV-Tra2 pRNAi后的致死性在二倍体后代中似乎比单倍体后代更明显。在我们的实验中，作为阳性对照的NV-tra pRNAi也观察到了这种二倍体致死效应。由于来自受精卵的二倍体胚胎除了具有母体染色体组外，还具有父系染色体组，这表明父系染色体组的存在或二倍体状态引起的剂量效应与NV-Tra2或NV-trA pRNAi诱导的玻璃新月球藻雄性发育是不相容的。NV-Tra2在激活雌性性别决定途径中的作用有助于更深入地了解Nasonia的性别决定机制。(C)2017年作者。爱思唯尔有限公司出版。
In insect sex determination a primary signal starts the genetic sex determination cascade that, in most insect orders, is subsequently transduced down the cascade by a transformer (tra) ortholog. Only a female-specifically spliced tra mRNA yields a functional TRA-protein that forms a complex with TRA2, encoded by a transformer-2 (tra2) ortholog, to act as a sex specific splicing regulator of the downstream transcription factors doublesex (dsx) and fruitless (fru). Here, we identify the tra2 ortholog of the haplodiploid parasitoid wasp N. vitripennis (Nv-tra2) and confirm its function in N. vitripennis sex determination. Knock down of Nv-tra2 by parental RNA interference (pRNAi) results in complete sex reversal of diploid offspring from female to male, indicating the requirement of Nv-tra2 for female sex determination. As Nv-tra2 pRNAi leads to frequent lethality in early developmental stages, maternal provision of Nv-tra2 transcripts is apparently also required for another, non-sex determining function during embryogenesis. In addition, lethality following Nv-tra2 pRNAi appears more pronounced in diploid than in haploid offspring. This diploid lethal effect was also observed following Nv-tra pRNAi, which served as a positive control in our experiments. As diploid embryos from fertilized eggs have a paternal chromosome set in addition to the maternal one, this suggests that either the presence of this paternal chromosome set or the dosage effect resulting from the diploid state is incompatible with the induced male development in N. vitripennis caused by either Nv-tra2 or Nv-tra pRNAi. The role of Nv-tra2 in activating the female sex determination pathway yields more insight into the sex determination mechanism of Nasonia. (C) 2017 The Authors. Published by Elsevier Ltd.