title: DNA synthesis during endomitosis is stimulated by insulin via the PI3K/Akt and TOR signaling pathways in the silk gland cells of Bombyx mori.
abstract: Silk gland cells undergo multiple endomitotic cell cycles during silkworm larval ontogeny. Our previous study demonstrated that feeding is required for continued endomitosis in the silk gland cells of silkworm larvae. Furthermore, the insulin signaling pathway is closely related to nutritional signals. To investigate whether the insulin signaling pathway is involved in endomitosis in silk gland cells, in this study, we initially analyzed the effects of bovine insulin on DNA synthesis in endomitotic silk gland cells using 5-bromo-2'-deoxyuridine (BrdU) labeling technology, and found that bovine insulin can stimulate DNA synthesis. Insulin signal transduction is mainly mediated via phosphoinositide 3-kinase (PI3K)/Akt, the target of rapamycin (TOR) and the extracellular signal-regulated kinase (ERK) pathways in vertebrates. We ascertained that these three pathways are involved in DNA synthesis in endomitotic silk gland cells using specific inhibitors against each pathway. Moreover, we investigated whether these three pathways are involved in insulin-stimulated DNA synthesis in endomitotic silk gland cells, and found that the PI3K/Akt and TOR pathways, but not the ERK pathway, are involved in this process. These results provide an important theoretical foundation for the further investigations of the mechanism underlying efficient endomitosis in silk gland cells.
authors: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China. lyfengcxy2010@163.com.
authors: Yaofeng
authors: Y
authors: Li
authors: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China. chenxyunxy@163.com.
authors: Xiangyun
authors: X
authors: Chen
authors: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China. txf0113@163.com.
authors: Xiaofang
authors: X
authors: Tang
authors: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China. zcd308@163.com.|Department of Biochemistry and Molecular Biology, Chongqing Medical University, Chongqing 400016, China. zcd308@163.com.
authors: Chundong
authors: C
authors: Zhang
authors: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China. wangla666@163.com.
authors: La
authors: L
authors: Wang
authors: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China. chenpengju1122@126.com.
authors: Peng
authors: P
authors: Chen
authors: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China. pmh0476@hotmail.com.|Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing 400716, China. pmh0476@hotmail.com.
authors: Minhui
authors: M
authors: Pan
authors: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China. lucheng@swu.edu.cn.|Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing 400716, China. lucheng@swu.edu.cn.
authors: Cheng
authors: C
authors: Lu
mesh_terms: D000818:Animals; D015153:Blotting, Western; D012831:Bombyx; D002478:Cells, Cultured; D004261:DNA Replication / Q000187:drug effects / Q000235:genetics; D007328:Insulin / Q000494:pharmacology*; D008938:Mitosis / Q000235:genetics / Q000502:physiology*; D051058:Oncogene Protein v-akt / Q000235:genetics / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D047011:Silk / Q000378:metabolism*
chemical_list: D007328:Insulin; D047011:Silk; D019869:Phosphatidylinositol 3-Kinases; D051058:Oncogene Protein v-akt