Expression and function of ecdysone receptor in tissue differentiation of insect

昆虫组织分化中蜕皮激素受体的表达及功能

基本信息

批准号：
08640844
负责人：
FUJIWARA Haruhiko
金额：
$ 1.34万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

项目摘要

Ecdysone, the insect molting hormone, penetrates into the target cells and binds to the ecdysone receptor (EcR) in the nuclei. this complex (ecdysone-EcR/USP) regulates a special set of gene expression and finally causes molts and metamorphosis of insects. I studied the molecular mechanisms of tissue differentiation during metamorphosis, mainly focused on relationship between EcR expression and the network of gene expressions induced by ecdysone. For this purpose, we first identified two isoforms of the silkworm EcR,BmEcR-A and BmEcR-B1, using by 5^1-RACE.Expression patterns of two EcR isoforms in different tissues during metamorphosis were analyzed by northern hybridization. Further, we determined the transcriptional initiation site for each EcR isoform and their flanking sequences. Interaction between these regions and putative transcription factors were studied by gel shift assay.Expression of EcR mRNA was induced by a very low dose of ecdysone (20 hydroxyecdysone). In the silkworm, Bombyx mori, BmEcR-B1 was expressed mainly during metamorphosis in most tissues only except anterior silk glands. This result is not consistent with the observation in Drosophila ; EcRB1 is predominant in larval tissues while EcRA is major in adult tissues. Thus, the relationship between developmental fate of tissues and patterns of EcR isoform expression is different in a lepidopteran insect. The start sites of transcription for BmEcR A and B1 are located more than 20kb from each other and we could not find homologous structure between them. In upstream regions of both start sites, there are initiator sequences instead of TATA box. Gel shift analysis implied that many factors are involved in transcriptional regulation and alternative promoting of BmEcR isoforms.

ecdysone是昆虫摩擦激素，渗透到靶细胞中，并与核中的Ecdysone受体（ECR）结合。这种复合物（Ecdysone-ECR/USP）调节了一组特殊的基因表达，并最终引起昆虫的蜕皮和变形。我研究了变态过程中组织分化的分子机制，主要集中于ECR表达与埃dy剂引起的基因表达网络之间的关系。为此，我们首先使用5^1-race。在变质过程中，通过北部杂交分析了两种ECR同工型的两种ECR同工型的两种ECR同工型的表达模式。此外，我们确定了每个ECR同工型及其侧翼序列的转录启动位点。这些区域之间的相互作用和推定的转录因子通过凝胶移位测定研究。ECR mRNA的表达是通过非常低剂量的Ecdysone（20羟基甲虫）诱导的。在蚕（Bombyx Mori）中，BMECR-B1主要在大多数组织中仅在变形过程中表达，仅在丝绸前丝腺以外。该结果与果蝇的观察不一致。 ECRB1在幼虫组织中主要是主导，而ECRA在成人组织中是主要的。因此，在鳞翅目昆虫中，组织的发育命运与ECR同工型表达的模式之间的关系不同。 BMECR A和B1的转录开始位点彼此之间超过20kb，我们在它们之间找不到同源结构。在两个启动站点的上游区域中，都有启动器序列而不是tata框。凝胶转移分析表明，许多因素参与转录调控和替代BMECR同工型的替代性。