昆虫激素体外调节家蚕滞育激素受体基因的表达

为了深入研究家蚕滞育的分子机理，从家蚕基因组中扩增了1395 bp和972 bp 2个不同长度的滞育激素受体基因Bmdhr启动子片段，以pGL3.0 Basic为载体，分别构建荧光素酶报告质粒，利用家蚕细胞瞬时表达系统分析其转录活性以及昆虫保幼激素类似物（JHA）、蜕皮激素（20-OH-ecdysone）和滞育激素（DH）对其活性的影响．结果表明：1395 bp的Bmdhr启动子活性显著低于972 bp的Bmdhr启动子，这说明Bmdhr启动子在-941～-1364 nt区间存在负调控元件．JHA浓度为2，4，6μg/mL时，极显著地增强启动子活性；浓度为1μg/mL时活性显著减弱，而为8μg/mL时则活性极显著减弱．20-OH-ecdysone对Bmdhr启动子活性的影响具有剂量效应，低浓度（1，2μg/mL）时显著增强启动子活性；浓度为4μg/mL时，启动子的活性显著减弱；但当浓度继续升高时，启动子活性又极显著增强．DH对Bmdhr启动子活性的影响同样具有剂量效应，其浓度为10～40 nM时，显著增强启动子活性；而当其浓度达到60 nM时，启动子活性变化不显著．

Insect hormones regulate expression of diapause hormone receptor gene of the silkworm (Bombyx mori) in vitro

To study the molecular mechanism of silkworm （Bombyx mori） diapause, two heterogeneous promoter fragments,1 395 bp and 972 bp,of diapause hormone receptor gene （Bmdhr） were cloned into pGL3.0 basic vector to construct reporter plasmids , respectively .The effects of foreign insect hormones including juvenile hormone ana -logue （ JHA） , 20-OH-ecdysone and diapause hormone （ DH） on regulation of Bmdhr promoter activities were ana-lyzed in BmN cells .The results showed that the activity of 1 395 bp promoter fragment was significantly lower than that of 972 bp one, implying that there is a negative regulation element between -941 and-1364 nt of Bmdhr pro-moter region.JHA of 2, 4 and 6μg/mL increased the promoter activity by 1.5~2.1 folds, but JHA of 8μg/mL decreased the promoter activity significantly .The effects of ecdysone on the Bmdhr promoter activity revealed a dosage dependent profile , low concentration ecdysone （1, 2μg/mL） increased the promoter activity significantly , ecdysone of 4μg/mL strongly suppressed the promoter activity .When ecdysone concentration increased from 6μg/mL to 8 and 10μg/mL,the promoter activity recovered and increased significantly again .The effects of DH re-vealed a dosage dependent profile too , low concentration DH （10, 20 and 40 nM） significantly enhanced the pro-moter activity , but high concentration DH （60 to 100 nM） showed no significant effect .