Zheng Y, Bi J, Hou M-Y, Shen W, Zhang W, Ai H, Yu X-Q, Wang Y-F
Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, China.
School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO, USA.
Insect Mol Biol. 2018 Oct;27(5):545-555. doi: 10.1111/imb.12393. Epub 2018 May 6.
The ocnus (ocn) gene encodes a protein abundant in the testes, implying its role in testis development. When Drosophila melanogaster is infected with the endosymbiont wMel Wolbachia, which affects the spermatogenesis of its hosts, ocn is downregulated in the third-instar larval testes, suggesting a role of ocn in spermatogenesis. In this study, we knocked down ocn in the testes and found that the hatch rates of embryos derived from ocn-knockdown males were significantly decreased, and 84.38% of the testes were much smaller in comparison to controls. Analysis of the smaller testes showed no germ cells but they had an extended hub. Using RNA-sequencing (RNA-Seq), we identified 69 genes with at least a twofold change (q-value < 5%) in their expression after ocn knockdown; of these, eight testes-specific and three reproduction-related genes were verified to be significantly downregulated using quantitative reverse transcription-PCR. Three genes (orientation disruptor, p24-2 and CG13541) were also significantly downregulated in the presence of Wolbachia. Furthermore, 98 genes were not expressed when ocn was knocked down in testes. These results suggest that ocn plays a crucial role in male germ cell development in Drosophila, possibly by regulating the expression of multiple spermatogenesis-related genes. Our data provide important information to help understand the molecular regulatory mechanisms underlying spermatogenesis.
ocnus（ocn）基因编码一种在睾丸中大量存在的蛋白质，这意味着它在睾丸发育中发挥作用。当黑腹果蝇感染内共生菌wMel沃尔巴克氏体时，其精子发生会受到影响，在三龄幼虫睾丸中ocn表达下调，这表明ocn在精子发生中具有作用。在本研究中，我们在睾丸中敲低ocn，发现来自ocn敲低雄性的胚胎孵化率显著降低，并且与对照组相比，84.38%的睾丸明显更小。对较小睾丸的分析显示没有生殖细胞，但它们有一个扩大的中心。使用RNA测序（RNA-Seq），我们鉴定出69个基因在ocn敲低后其表达至少有两倍变化（q值<5%）；其中，8个睾丸特异性基因和3个与生殖相关的基因通过定量逆转录PCR验证显著下调。在存在沃尔巴克氏体的情况下，3个基因（定向破坏因子、p24-2和CG13541）也显著下调。此外，当睾丸中ocn被敲低时，98个基因不表达。这些结果表明ocn在果蝇雄性生殖细胞发育中起关键作用，可能是通过调节多个精子发生相关基因的表达。我们的数据为理解精子发生的分子调控机制提供了重要信息。
