›› 2017, Vol. 60 ›› Issue (12): 1367-1375.doi: 10.16380/j.kcxb.2017.12.002

• RESEARCH PAPERS • Previous Articles     Next Articles

Regulation of the expression of vitellogenin gene by vertebrate estrogen and a microscale thermophoresis assay of its interaction with ecdysone receptors in the silkworm, Bombyx mori (Lepidoptera: Bombycidae)

WANG Yong1,2, PENG Chu-Yue1,2, WU Jin-Xin1, SHEN Guan-Wang1, LIN Ying1.*, XIA Qing-You1   

  1. (1. State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China; 2. College of Biotechnology in Southwest University, Chongqing 400716,China)
  • Online:2017-12-20 Published:2017-12-20

Abstract: 【Aim】 Estradiol (E2), an estrogen hormone, regulates the growth and reproduction through estrogen receptors (ERs) in vertebrates. There is no ER in insects, but studies showed that some insects can respond to E2. In this study, the possible regulatory mechanisms of the expression of vitellogenin gene by E2 was elucidated in the silkworm, Bombyx mori, after confirming that E2 influenced the expression of BmVg in female larvae of the silkworm. 【Methods】 The expression level of BmVg was detected in the fat body of female larvae (60 h after mounting) of B. mori after in vitro treatment with different concentrations of E2 (0.001, 0.05, 0.5, 5 and 50 nmol/L) by qRT-PCR, and the response of the silkworm to E2 was analyzed. The ecdysone receptor gene of B. mori (BmEcRB1) was cloned and its prokaryotic expression vector was constructed. The BmEcRB1 protein was purified and incubated with E2 in vitro, and the binding characteristics of E2 to BmEcRB1 were assayed by microscale thermophoresis (MST). 【Results】 Different concentrations of E2 significantly inhibited the expression of BmVg of female larvae of B. mori after in vitro culture, and the inhibitory effect was more obvious with the increase of E2 concentration. MST results showed that E2 had a certain affinity with BmEcRB1, with the dissociation constant (Kd) value of 77.8±22 μmol/L. 【Conclusion】 The results suggest that E2 inhibits the expression of BmVg in the silkworm through competition with ecdysone to bind BmEcRB1.

Key words:  Bombyx mori, estradiol, ecdysone, vitellogenin, ecdysone receptor, gene expression, microscale thermophoresis (MST)