Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400716, China; Chongqing Key Laboratory of Sericultural Science, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Chongqing 400715, China.
Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400716, China; Chongqing Key Laboratory of Sericultural Science, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Chongqing 400715, China.
Int J Biol Macromol. 2024 Oct;277(Pt 3):134312. doi: 10.1016/j.ijbiomac.2024.134312. Epub 2024 Jul 29.
The silkworm is an incredibly valuable insect that produces silk through its silk gland. Within this organ, Fibroinase has been identified and named due to its ability to fibroin degradation. The expression of Fibroinase in the silk gland significantly increases during the larval-pupal stage, which might be associated with the degeneration of the silk gland. In this study, Fibroinase was overexpressed and knocked down specifically both in the middle and posterior silk glands, respectively, using transgenic technology. The investigation of silk gland development in these transgenic silkworms showed that Fibroinase plays a direct role in accelerating silk gland degeneration. The staining analyses performed in the silk glands of transgenic silkworms suggest that Fibroinase is involved in the processes of autophagy and apoptosis during silk gland degeneration. Further experiments demonstrated that Fibroinase, acting as a lysosomal regulator, negatively regulates autophagy via the mTOR (mechanistic target of rapamycin) pathway. Moreover, during apoptosis, Fibroinase could activate Caspase3 by increasing the activity of BmCaspase1, ultimately accelerating the apoptosis process. These findings enhance our understanding of the physiological role of Fibroinase in promoting silk gland degeneration, which plays a role in breaking down proteins in the silk gland and coordinating the regulation of autophagy and apoptosis.
家蚕是一种非常有价值的昆虫，它通过丝腺产生丝。在这个器官中，由于其能够降解丝素，因此鉴定并命名为丝素酶。丝素酶在家蚕幼虫-蛹期的表达显著增加，这可能与丝腺的退化有关。在这项研究中，利用转基因技术分别在家蚕中肠和后肠特异性过表达和敲低丝素酶。对这些转基因家蚕的丝腺发育的研究表明，丝素酶在加速丝腺退化中起着直接作用。对转基因家蚕丝腺的染色分析表明，丝素酶参与丝腺退化过程中的自噬和细胞凋亡。进一步的实验表明，丝素酶作为溶酶体调节剂，通过 mTOR（雷帕霉素靶蛋白）途径负调控自噬。此外，在细胞凋亡过程中，丝素酶可以通过增加 BmCaspase1 的活性来激活 Caspase3，从而加速细胞凋亡过程。这些发现提高了我们对丝素酶在促进丝腺退化中的生理作用的理解，丝素酶在丝腺中降解蛋白质和协调自噬和细胞凋亡的调节中发挥作用。
