Effects of starvation and hormones on DNA synthesis in silk gland cells of the silkworm, Bombyx moil

作     者：Yao-Feng Li Xiang-Yun Chen Chun-Dong Zhang Xiao-Fang Tang La Wang Tai-Hang Liu Min-Hui Pan Cheng Lu 无

作者机构：State Key Laboratory of Silkworm Genome Biology Southwest University Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry Southwest University Chongqing Department of Biochemistry and Molecular Biology Chongqing Medical University Chongqing China 

出 版 物：《Insect Science》 (昆虫科学（英文版）)

年 卷 期：2016年第23卷第4期

页      面：569-578页

核心收录：

学科分类：0710[理学-生物学] 0830[工学-环境科学与工程（可授工学、理学、农学学位）] 07[理学] 08[工学] 0815[工学-水利工程] 0904[农学-植物保护] 0901[农学-作物学] 071002[理学-动物学] 0713[理学-生态学] 

基　　金：This work was supported by the National Natural Science Foundation of China (Nos. 31172269 and 31272505)  and the Specialized Research Fund for the Doctoral Program of Higher Education (No. 20120182110010) 

主　　题：Bombyx mori DNA synthesis endomitosis silk gland starvation 20-hydroxyecdysone 

摘      要：Silk gland cells of silkworm larvae undergo multiple cycles of endomitosis for the synthesis of silk proteins during the spinning phase. In this paper, we analyzed the endomitotic DNA synthesis of silk gland cells during larval development, and found that it was a periodic fluctuation, increasing during the vigorous feeding phase and being gradually inhibited in the next molting phase. That means it might be activated by a self- regulating process after molting. The expression levels of cyclin E, cdtl and pcna were consistent with these developmental changes. Moreover, we further examined whether these changes in endomitotic DNA synthesis resulted from feeding or hormonal stimulation. The results showed that DNA synthesis could be inhibited by starvation and re-activated by re-feeding, and therefore appears to be dependent on nutrition. DNA synthesis was suppressed by in vivo treatment with 20-hydroxyecdysone （20E）. However, there was no effect on DNA synthesis by in vitro 20E treatment or by either in vivo or in vitro juvenile hormone treatment. The levels of Akt and 4E-BP phosphorylation in the silk glands were also reduced by starvation and in vivo treatment with 20E. These results indicate that the activation of endomitotic DNA synthesis during the intermolt stages is related to feeding and DNA synthesis is inhibited indirectly by 20E.