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 200032, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Genes (Basel). 2021 Feb 23;12(2):315. doi: 10.3390/genes12020315.
In insects, sex determination pathways involve three levels of master regulators: primary signals, which determine the sex; executors, which control sex-specific differentiation of tissues and organs; and transducers, which link the primary signals to the executors. The primary signals differ widely among insect species. In Diptera alone, several unrelated primary sex determiners have been identified. However, the () gene is highly conserved as the executor component across multiple insect orders. The transducer level shows an intermediate level of conservation. In many, but not all examined insects, a key transducer role is performed by (), which controls sex-specific splicing of . In Lepidoptera, studies of sex determination have focused on the lepidopteran model species (the silkworm). In the primary signal of sex determination cascade starts from , a female-specific PIWI-interacting RNA, and its targeting gene , which is apparently specific to and conserved among Lepidoptera. has not been found in Lepidoptera. Instead, the PSI protein binds directly to pre-mRNA and regulates its alternative splicing to produce male- and female-specific transcripts. Despite this basic understanding of the molecular mechanisms underlying sex determination, the links among the primary signals, transducers and executors remain largely unknown in Lepidoptera. In this review, we focus on the latest findings regarding the functions and working mechanisms of genes involved in feminization and masculinization in Lepidoptera and discuss directions for future research of sex determination in the silkworm.
在昆虫中，性别决定途径涉及三个级别的主调控因子：决定性别 的初级信号；控制组织和器官性别特化的执行器；以及将初级信号连接到执行器的传感器。初级信号在不同的昆虫物种中差异很大。仅在双翅目昆虫中，就已经确定了几种不相关的初级性别决定因子。然而， （）基因作为执行器成分在多个昆虫目之间高度保守。传感器水平显示出中间水平的保守性。在许多（但不是所有检查过的）昆虫中，关键的传感器作用是由 （）执行的，它控制 （）的性别特异性剪接。在鳞翅目昆虫中，性别决定的研究集中在鳞翅目模式物种 （家蚕）上。在家蚕中，性别决定级联的初级信号始于 ，一种雌性特异性 PIWI 相互作用 RNA 及其靶基因 ，它显然是鳞翅目特有的且在鳞翅目之间保守。在鳞翅目昆虫中尚未发现 。相反，PSI 蛋白直接结合到 前体 mRNA 并调节其选择性剪接，以产生雄性和雌性特异性转录本。尽管对性别决定的分子机制有了基本的了解，但在鳞翅目昆虫中，初级信号、传感器和执行器之间的联系在很大程度上仍然未知。在这篇综述中，我们重点介绍了关于参与鳞翅目雌性化和雄性化的基因的最新发现，并讨论了家蚕性别决定未来研究的方向。
