Abstract：
In insects, melanism, a fundamental pigmentation process, is of significant importance in evolutionary biology due to its complex genetic foundation. We investigated the role of the RNA-binding gene Musashi (msi) in melanism in Laodelphax striatellus, a Hemiptera species. We identified a single L. striatellus msi homolog, Lsmsi, encoding a 357 amino acid protein with 2 RNA recognition motifs. RNA interference-mediated knockdown of LsMsi resulted in complete body melanism and increased cuticular permeability. Additionally, we found the involvement of G protein-coupled receptor A42 and tyrosine hydroxylase (Th) in L. striatellus melanism. Knockdown of LsTh lightened the epidermis, showing dehydration signs, while LsA42 knockdown enhanced LsTh expression, leading to melanism. Surprisingly, Lsmsi knockdown decreased both LsA42 and LsTh expression, which was expected to cause whitening but resulted in melanism. Further, we found that Lsmsi influenced downstream genes like phenoloxidase homolog LsPo and dopa decarboxylase (Ddc) homolog LsDdc in the tyrosine-mediated melanism pathway. Extending to Nilaparvata lugens and Sogatella furcifera, we demonstrated the conserved role of msi in melanism among Delphacidae. Given MSI proteins\' roles in cancer and tumors in vertebrates, our study is the first to link msi in insects to Delphacidae body color melanization via the tyrosine-mediated pathway, offering fresh perspectives on the genetic basis of insect melanism and msi functions.
摘要：
在昆虫中，黑色素症,一个基本的色素沉着过程，由于其复杂的遗传基础，在进化生物学中具有重要意义。我们研究了RNA结合基因Musashi（msi）在Laodelphasx纹状体黑色素中的作用，一种半翅目。我们确定了一个单一的纹状体msi同源物，Lsmsi,编码具有2个RNA识别基序的357个氨基酸的蛋白质。RNA干扰介导的LsMsi敲低导致完全的身体黑变和增加的角质层通透性。此外,我们发现G蛋白偶联受体A42和酪氨酸羟化酶（Th）参与纹状体黑变。LsTh的击倒减轻了表皮，有脱水迹象,而LsA42敲低增强LsTh表达，导致黑色素沉着。令人惊讶的是,Lsmsi敲除降低LsA42和LsTh表达,预计会导致美白，但导致黑色素沉着。Further,我们发现Lsmsi在酪氨酸介导的黑化途径中影响了下游基因,如酚氧化酶同源物LsPo和多巴脱羧酶(Ddc)同源物LsDdc.延伸到Nilaparvatalugens和Sogatellafurcifera，我们证明了msi在Delphacidae黑化中的保守作用。鉴于MSI蛋白在脊椎动物癌症和肿瘤中的作用，我们的研究首次通过酪氨酸介导的途径将昆虫中的msi与Delphacidae体色黑化联系起来，提供关于昆虫黑化和msi功能的遗传基础的新观点。
