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蜕皮激素(20E)和保幼激素(JH)具有共同调控家蚕丝蛋白合成的作用.将家蚕5龄第3天幼虫的中部和后部丝腺置于含不同浓度20E或JH的培养基中进行离体培养,于培养不同时间通过定量PCR检测丝素蛋白基因及丝胶蛋白基因的表达变化.结果表明,蜕皮激素处理对丝蛋白基因表达的影响,因激素使用剂量和作用时间不同而异;保幼激素处理会抑制丝蛋白基因的表达,尤其对丝素蛋白重链基因Bmfib-H的表达抑制作用更为明显,50 ng/mL JH处理48 h后Bmfib-H的表达水平下调1倍左右;蜕皮激素和保幼激素共同处理比单一激素处理更有助于丝蛋白基因的表达,但用保幼激素先处理丝腺24 h后再用蜕皮激素和保幼激素共同处理,会显著抑制丝素蛋白轻链基因Bmfib-L的表达.试验在排除蚕体内源激素干扰的条件下,从转录水平初步分析了保幼激素和蜕皮激素对家蚕丝蛋白基因表达的调控机制.“,”Ecdysone (20E) and juvenile hormone (JH) jointly regulate the synthesis of silk proteins in silkworm (Bombyx mori).In this study,middle and posterior silk glands from day 3 silkworm larvae of the 5th instar were cultured in vitro and treated with different concentrations of 20E or JH,the expression changes of sericin genes and fibroin genes were detected by qRT-PCR at different time points after treatment.The results showed that,the effect of ecdysone treatment on expression of silk protein genes varied with hormone dosage and treatment time.The expression of silk fibroin genes,especially the fibroin heavy chain gene (Bmfib-H),was inhibited by JH treatment,which was reduced by nearly 1 fold after 48 h treatment with 50 ng/mL JH.Combined treatment with 20E and JH was more favorable for expression of silk protein genes than treatment with single hormone.However,24 h pretreatment with JH and followed by combined treatment with 20E and JH significantly inhibited the expression of fibroin light chain gene (Bmfib-L).The regulatory mechanism of ecdysone and juvenile hormone on expression of silk protein genes was studied at molecular level on condition free of endogenous hormones.