Beatty J, Fauth T, Callender J L, Spindler-Barth M, Henrich V C
Center for Biotechnology, Genomics and Health Research, University of North Carolina-Greensboro, Greensboro, NC 27402-6170, USA.
Insect Mol Biol. 2006 Dec;15(6):785-95. doi: 10.1111/j.1365-2583.2006.00683.x.
Ecdysteroid regulation of gene transcription in Drosophila melanogaster and other insects is mediated by a heterodimer comprised of Ultraspiracle (USP) and one of three ecdysone receptor (EcR) isoforms (A, B1 and B2). This study revealed that the EcR/USP heterodimer displays isoform-specific capabilities. EcRB1 is normally induced with a form of USP that is missing its DNA-binding domain (DBD), although potentiation by juvenile hormone (JH) III is reduced. The EcRA and B2 isoforms, however, display almost no response to ecdysteroids with the DBD(-) USP. A mutation, K497E, in the shared ligand-binding domain of the EcR isoforms caused elevated EcRB2-specific affinity for a canonical ecdysone response element. The effects of directed modification and mutagenesis offer a strategy for developing hypotheses and considerations for studying in vivo function.
在黑腹果蝇和其他昆虫中，蜕皮甾类对基因转录的调控是由超气门蛋白（USP）和三种蜕皮激素受体（EcR）亚型（A、B1和B2）之一组成的异二聚体介导的。这项研究表明，EcR/USP异二聚体具有亚型特异性能力。EcRB1通常与一种缺失其DNA结合结构域（DBD）的USP形式一起被诱导，尽管保幼激素（JH）III的增强作用有所降低。然而，EcRA和B2亚型对具有DBD（-）USP的蜕皮甾类几乎没有反应。EcR亚型共享的配体结合结构域中的一个突变K497E导致EcRB2对典型蜕皮激素反应元件的亲和力升高。定向修饰和诱变的作用为研究体内功能提供了一种提出假设和进行思考的策略。
