【摘要】 昆虫蜕皮激素通过与蜕皮激素受体(EcR)和超气门蛋白(USP)形成的异源二聚体相互作用,起始包括转录因子表达在内的蜕皮级联反应,引起昆虫蜕皮。为了探究家蚕蜕皮激素受体基因EcR-B1(BmEcR-B1)表达的调控机制,利用双荧光素酶报告系统和Bac-to-Bac表达系统检测家蚕幼虫经蜕皮激素诱导后,脂肪体、马氏管、中肠组织内不同缺失片段的BmEcR-B1启动子活性。对各组织样品的检测结果均证明:BmEcR-B1启动子-138~-11 bp之间存在正调控元件,并且其活性能被蜕皮激素诱导。在细胞水平上进一步分析BmEcR-B1启动子调控区域,结果显示在-138~-108 bp区域包含的调控元件对于BmEcR-B1启动子的转录调控是必需的,序列分析显示这一区域包含有畸形基因编码蛋白Dfd和热休克转录因子(HSF)2个转录调控元件的结合位点。研究结果为探索BmEcR-B1在家蚕变态发育中的转录调控机制提供了有益线索。更多还原

【Abstract】 Ecdysteroid interacts with the heterodimer formed between ecdysone receptor(EcR) and ultraspiracle protein(USP) to initiate the cascade reactions including the expression of transcription factors that result in insect molting. To analyze the regulatory mechanism of EcR-B1 gene expression in silkworm(Bombyx mori),promoter activity of EcR-B1 gene with various deletions in the promoter regulatory region was determined using the dual luciferase reporter assay and Bac-to-Bac expression system in fat body,Malpighian tubule and midgut of silkworm larvae after induction with ecdysone(20E). The results showed that positive regulatory elements existed at position-138 to-11 bp in BmEcR-B1 gene region,of which activity could be induced by ecdysone. Further analysis of the BmEcR-B1 promoter at cellular level suggested that region-138 to-108 bp contained important regulatory elements that were necessary for transcriptional regulation of BmEcR-B1 promoter. Sequence analysis revealed that these regions had several transcriptional regulatory elements including Drosophila Dfd and HSF transcription factor binding sites. This study provides a useful clue for investigating transcriptional regulation mechanism of BmEcR-B1 gene during metamorphosis of silkworm.更多还原