Zhou Linli, Liu Shuo, Li Chunlin, Zhou Wei, Dai Fangyin, Tong Xiaoling
State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China; Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Southwest University, Chongqing 400715, China.
State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China.
Int J Biol Macromol. 2025 Feb;291:138916. doi: 10.1016/j.ijbiomac.2024.138916. Epub 2024 Dec 18.
Endoreplication is particularly important in the context of silk protein synthesis within the silk gland cells of silkworms. Our previous research indicated that the BmE2F1 enhances the silk yield of silkworm cocoons, but the underlying molecular mechanism remains elusive. In this study, we employed RNA-sequencing to dissect the transcriptional profiles of silk glands in the wild-type Dazao silkworm strain and the overexpression (OE) silkworm strain with specific overexpression of the BmE2F1 gene in silk glands. Among the 1126 differentially expressed genes (DEGs), many related to DNA replication (endoreplication in silk glands of silkworm larvae) were significantly enriched. Quantitative real-time PCR confirmed that overexpression of BmE2F1 led to a substantial increase in the expression of 13 genes involved in the DNA replication pathway. Additionally, BmE2F1 upregulated the expression of BmCyclin E, a pivotal gene in the G/S phase transition. Moreover, BmE2F1 overexpression in silk glands significantly boosted DNA replication and concurrently increased the DNA content within silk glands. In conclusion, BmE2F1 regulates endoreplication in silk gland cells of silkworms through dual mechanisms: firstly, by enhancing the formation of the DNA replication complex; and secondly, by facilitating the cells' entry into the S phase.
核内复制在蚕的丝腺细胞内丝蛋白合成的背景下尤为重要。我们之前的研究表明，BmE2F1可提高蚕茧的丝产量，但其潜在的分子机制仍不清楚。在本研究中，我们采用RNA测序技术剖析了野生型大造蚕品系以及丝腺中特异性过表达BmE2F1基因的过表达（OE）蚕品系的丝腺转录谱。在1126个差异表达基因（DEG）中，许多与DNA复制（家蚕幼虫丝腺中的核内复制）相关的基因显著富集。定量实时PCR证实，BmE2F1的过表达导致参与DNA复制途径的13个基因的表达大幅增加。此外，BmE2F1上调了G/S期转换中的关键基因BmCyclin E的表达。此外，丝腺中BmE2F1的过表达显著促进了DNA复制，并同时增加了丝腺内的DNA含量。总之，BmE2F1通过双重机制调节家蚕丝腺细胞中的核内复制：第一，通过增强DNA复制复合体的形成；第二，通过促进细胞进入S期。
