Wolbachia is a genus of endosymbiotic bacteria that induce a wide range of effects on their insect hosts. Cytoplasmic incompatibility (CI) is the most common phenotype mediated by Wolbachia and results in embryonic lethality when Wolbachia-infected males mate with uninfected females. Studies have revealed that bacteria can regulate many cellular processes in their hosts using small non-coding RNAs, so we investigated the involvement of small RNAs (sRNAs) in CI. Comparison of sRNA libraries between Wolbachia-infected and uninfected Drosophila melanogaster testes revealed 18 novel microRNAs (miRNAs), of which 12 were expressed specifically in Wolbachia-infected flies and one specifically in Wolbachia-uninfected flies. Furthermore, ten miRNAs showed differential expression, with four upregulated and six downregulated in Wolbachia-infected flies. Of the upregulated miRNAs, nov-miR-12 exhibited the highest upregulation in the testes of D. melanogaster. We then identified pipsqueak (psq) as the target gene of nov-miR-12 with the greatest complementarity in its 3' untranslated region (UTR). Wolbachia infection was correlated with reduced psq expression in D. melanogaster, and luciferase assays demonstrated that nov-miR-12 could downregulate psq through binding to its 3'UTR region. Knockdown of psq in Wolbachia-free fly testes significantly reduced egg hatching rate and mimicked the cellular abnormalities of Wolbachia-induced CI in embryos, including asynchronous nuclear division, chromatin bridging, and chromatin fragmentation. These results suggest that Wolbachia may induce CI in insect hosts by miRNA-mediated changes in host gene expression. Moreover, these findings reveal a potential molecular strategy for elucidating the complex interactions between endosymbionts and their insect hosts, such as Wolbachia-driven CI.

中文翻译：

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小RNA分析为Wolbachia诱导的果蝇果蝇的细胞质不相容性提供了新的见解。

沃尔巴克氏菌是内共生细菌的一种，对它们的昆虫宿主产生广泛的影响。细胞质不相容性（CI）是由Wolbachia介导的最常见表型，当感染Wolbachia的雄性与未感染的雌性交配时，会导致胚胎致死。研究表明，细菌可以使用小的非编码RNA调节宿主中的许多细胞过程，因此我们调查了CI中小RNA（sRNA）的参与。在感染了Wolbachia的果蝇睾丸和未感染的果蝇的睾丸中比较sRNA文库，发现有18种新颖的microRNA（miRNA），其中12种在Wolbachia感染的果蝇中特异性表达，一种在Wolbachia感染的果蝇中特异性表达。此外，在感染了Wolbachia的果蝇中，十个miRNA显示差异表达，其中四个上调，六个下调。在上调的miRNA中，nov-miR-12在黑腹果蝇的睾丸中表现出最高的上调。然后，我们确定pipsqueak（psq）为nov-miR-12的靶基因，其3'非翻译区（UTR）具有最大的互补性。Wolbachia感染与黑腹果蝇中psq表达的降低有关，萤光素酶检测表明nov-miR-12可以通过与其3'UTR区结合来下调psq。剔除无Wolbachia蝇fly的psq可以显着降低卵的孵化率，并模仿Wolbachia诱导的CI在胚胎中的细胞异常，包括异步核分裂，染色质桥接和染色质碎裂。这些结果表明，Wolbachia可能通过miRNA介导的宿主基因表达变化诱导昆虫宿主中的CI。此外，