DDX3 represents a well‐defined subfamily of DEAD‐box RNA helicase and exerts multiple functions in RNA metabolism, cell cycle, tumorigenesis, signal pathway, and fertility. Our previous study has shown that LmDDX3, the ortholog of DDX3 in Locusta migratoria, is ubiquitously expressed, and with a high abundance in testis and ovary. Knockdown of LmDDX3 results in a lethal phenotype in nymph, but it still remains unclear for its role in reproductive process. In this study, we therefore characterized LmDDX3 expression in female adult locust and analyzed its function in oocyte development. LmDDX3 was expressed in all tissues examined with significant more transcripts in ovary and hindgut. In ovary, a strong expression level was detected at the day just after adult eclosion, and a dramatic reduction then occurred during the oocyte development. LmDDX3 RNAi led to a reduced vitellogenin (Vg) expression in fat body via partially at least, the JH signaling pathway, and caused an upregulation of vitellogenin receptor (VgR) in ovary, and thus blocked the ovarian development and oocyte maturation. Sequence and phylogenetic analysis indicated that LmDDX3 was closely related to termite DDX3. Taken together, these data reveal a critical role for LmDDX3 in regulating the transcription of Vg and VgR, two major factors in vitellogenesis that is a key process required for ovary development and oocyte maturation in locust, and contribute thereof a new putative target for locust biological control.

中文翻译：

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RNA解旋酶DDX3是东方蝗的卵巢发育和卵母细胞成熟所必需的

DDX3代表DEAD-box RNA解旋酶的一个明确定义的亚家族，并在RNA代谢，细胞周期，肿瘤发生，信号途径和生育力中发挥多种功能。我们以前的研究已经表明，LmDDX3，的直系同源基因DDX3在飞蝗，广泛表达，并配有高丰度在睾丸和卵巢。击倒LmDDX3会导致若虫的致死表型，但仍不清楚其在生殖过程中的作用。因此，在这项研究中，我们表征了LmDDX3在成年蝗虫中的表达，并分析了其在卵母细胞发育中的功能。LmDDX3在卵巢和后肠中所有转录本上都有明显的转录本表达。在卵巢中，在成年羽化后的第二天就检测到了强表达水平，然后在卵母细胞发育过程中发生了显着的降低。LmDDX3 RNAi至少部分通过JH信号通路导致脂肪体中的卵黄蛋白原（Vg）表达降低，并导致卵巢中卵黄蛋白原受体（VgR）上调，从而阻断了卵巢的发育和卵母细胞的成熟。序列分析和系统发育分析表明，LmDDX3与白蚁DDX3密切相关。综上所述，这些数据揭示了LmDDX3的关键作用在调节Vg和VgR的转录中，卵黄发生中的两个主要因素是蝗虫卵巢发育和卵母细胞成熟所需的关键过程，并为蝗虫的生物学控制提供了新的靶点。