Masculinizer is not post-transcriptionally regulated by female-specific piRNAs during sex determination in the Asian corn borer, Ostrinia furnacalis
Masculinizer is not post-transcriptionally regulated by female-specific piRNAs during sex determination in the Asian corn borer, Ostrinia furnacalis
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DOI：
10.1016/j.ibmb.2023.103946
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发表时间：
2023-04-21
影响因子：
3.8
通讯作者：
Katsuma，Susumu
中科院分区：
文献类型：
--
作者：
Fukui，Takahiro;Shoji，Keisuke;Katsuma，Susumu
鳞翅目昆虫雌性是异配生殖的，尽管大多数昆虫物种雄性是异配生殖的。在鳞翅目模式种家蚕（B. mori）的雌性W染色体上发现了最高的性别决定因子Feminizer（Fem），Fem是PIWI相互作用小RNA（皮尔纳）的前体，FempiRNA与Siwi形成复合物，Siwi是家蚕PIWI进化枝Argonaute蛋白之一。在雌性胚胎中，FempiRNA-Siwi复合物切割雄性决定基因Masculinizer（Masc）的mRNA，指导雌性决定途径。在雄性胚胎中，Masc 3在缺乏FempiRNA的情况下激活雄性决定途径。最近，在小菜蛾Plutella xylostella（Yponomeutoidea）中也发现了与MascmRNA互补的W染色体来源的piRNA，表明鳞翅目昆虫的性别决定依赖于piRNA的趋同进化。在这里，我们表明，这是不是在亚洲玉米螟，Ostriniafurnacalis（Pyraloidea）的情况。虽然我们以前的研究表明，O. dumacalis Masc（OfMasc）在胚胎阶段具有雄性化功能，但在性别决定的时间点，OfMasc的表达水平在性别之间是无法区分的。深度测序分析没有发现定位在MascmRNA上的雌性特异性小RNA。两个PIWI基因的胚胎敲除不影响OfMascin的表达水平。这些结果表明，雌虫胚胎中MascmRNA的piRNA依赖性减少不是性别决定的常见策略，这表明性别决定因子在鳞翅目中可能存在分歧进化。
Lepidopteran insects are heterogametic in females, although most insect species are heterogametic in males. In a lepidopteran model species, the silkwormBombyxmori(Bombycoidea), the uppermost sex determinantFeminizer(Fem) has been identified on the female-specific W chromosome.Femis a precursor of PIWI-interacting small RNA (piRNA).FempiRNA forms a complex with Siwi, one of the twoB.moriPIWI-clade Argonaute proteins. In female embryos,FempiRNA–Siwi complex cleaves the mRNA of the male-determining geneMasculinizer(Masc), directing the female-determining pathway. In male embryos,Mascactivates the male-determining pathway in the absence ofFempiRNA. Recently, W chromosome-derived piRNAs complementary toMascmRNA have also been identified in the diamondback mothPlutella xylostella(Yponomeutoidea), indicating the convergent evolution of piRNA-dependent sex determination in Lepidoptera. Here, we show that this is not the case in the Asian corn borer,Ostriniafurnacalis(Pyraloidea). Although our previous studies demonstrated thatO.furnacalis Masc(OfMasc) has a masculinizing function in the embryonic stage, the expression level ofOfMascwas indistinguishable between the sexes at the timing of sex determination. Deep sequencing analysis identified no female-specific small RNAs mapped ontoOfMascmRNA. Embryonic knockdown of twoPIWIgenes did not affect the expression level ofOfMascin either sex. These results demonstrated that piRNA-dependent reduction ofMascmRNA in female embryos is not a common strategy of sex determination, which suggests the possibility of divergent evolution of sex determinants across the order Lepidoptera.