Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.
CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China.
PLoS Genet. 2020 Nov 2;16(11):e1009194. doi: 10.1371/journal.pgen.1009194. eCollection 2020 Nov.
Sex determination pathways are astoundingly diverse in insects. For instance, the silk moth Bombyx mori uniquely use various components of the piRNA pathway to produce the Fem signal for specification of the female fate. In this study, we identified BmGTSF1 as a novel piRNA factor which participates in B. mori sex determination. We found that BmGtsf1 has a distinct expression pattern compared to Drosophila and mouse. CRISPR/Cas9 induced mutation in BmGtsf1 resulted in partial sex reversal in genotypically female animals by shifting expression of the downstream targets BmMasc and Bmdsx to the male pattern. As levels of Fem piRNAs were substantially reduced in female mutants, we concluded that BmGtsf1 plays a critical role in the biogenesis of the feminizing signal. We also demonstrated that BmGTSF1 physically interacted with BmSIWI, a protein previously reported to be involved in female sex determination, indicating BmGTSF1 function as the cofactor of BmSIWI. BmGtsf1 mutation resulted in piRNA pathway dysregulation, including piRNA biogenesis defects and transposon derepression, suggesting BmGtsf1 is also a piRNA factor in the silkworm. Furthermore, we found that BmGtsf1 mutation leads to gametogenesis defects in both male and female. Our data suggested that BmGtsf1 is a new component involved in the sex determination pathway in B. mori.
昆虫的性别决定途径令人惊讶地多样化。例如，丝蚕 Bombyx mori 独特地利用 piRNA 途径的各种成分来产生 Fem 信号，以指定雌性命运。在这项研究中，我们鉴定出 BmGTSF1 是一种参与 B. mori 性别决定的新型 piRNA 因子。我们发现 BmGtsf1 的表达模式与果蝇和小鼠明显不同。CRISPR/Cas9 诱导的 BmGtsf1 突变导致基因型为雌性的动物部分性别反转，将下游靶标 BmMasc 和 Bmdsx 的表达转移到雄性模式。由于 Fem piRNAs 的水平在雌性突变体中显著降低，我们得出结论，BmGtsf1 在雌性化信号的生物发生中发挥关键作用。我们还证明 BmGTSF1 与 BmSIWI 相互作用，BmSIWI 是先前报道参与雌性性别决定的蛋白质，表明 BmGTSF1 作为 BmSIWI 的辅助因子发挥作用。BmGtsf1 突变导致 piRNA 途径失调，包括 piRNA 生物发生缺陷和转座子去抑制，表明 BmGtsf1 也是丝蚕中的 piRNA 因子。此外，我们发现 BmGtsf1 突变导致雄性和雌性的配子发生缺陷。我们的数据表明，BmGtsf1 是 B. mori 性别决定途径中的一个新成分。
