Hammond S Austin, Veldhoen Nik, Kobylarz Marek, Webber Nicholas R, Jordan Jameson, Rehaume Vicki, Boone Michelle D, Helbing Caren C
Department of Biochemistry & Microbiology, University of Victoria, Canada.
Zoolog Sci. 2013 May;30(5):392-401. doi: 10.2108/zsj.30.392.
Postembryonic development of a larval tadpole into a juvenile frog involves the coordinated action of thyroid hormone (TH) across a diversity of tissues. Changes in the frog transcriptome represent a highly sensitive endpoint in the detection of developmental progression, and for the identification of environmental chemical contaminants that possess endocrine disruptive properties. Unfortunately, in contrast with their vital role as sentinels of environmental change, few gene expression tools currently exist for the majority of native North American frog species. We have isolated seven expressed gene sequences from the Northern green frog (Rana clamitans melanota) that encode proteins associated with TH-mediated postembryonic development and global stress response, and established a quantitative real-time polymerase chain reaction (qPCR) assay. We also obtained three additional species-specific gene sequences that functioned in the normalization of the expression data. Alterations in mRNA abundance profiles were identified in up to eight tissues during R. clamitans postembryonic development, and following exogenous administration of TH to premetamorphic tadpoles. Our results characterize tissue distribution and sensitivity to TH of select mRNA of a common North American frog species and support the potential use of this qPCR assay in identification of the presence of chemical agents in aquatic environments that modulate TH action.
幼体蝌蚪发育为幼蛙的胚后发育过程涉及甲状腺激素（TH）在多种组织中的协同作用。青蛙转录组的变化是检测发育进程以及识别具有内分泌干扰特性的环境化学污染物的高度敏感指标。遗憾的是，尽管青蛙作为环境变化的哨兵起着至关重要的作用，但目前针对大多数北美本土蛙类物种的基因表达工具却很少。我们从北美绿蛙（Rana clamitans melanota）中分离出七个表达的基因序列，这些序列编码与TH介导的胚后发育和整体应激反应相关的蛋白质，并建立了定量实时聚合酶链反应（qPCR）检测方法。我们还获得了另外三个物种特异性基因序列，用于对表达数据进行标准化。在北美绿蛙胚后发育期间以及向变态前的蝌蚪外源施用TH后，在多达八个组织中鉴定出了mRNA丰度谱的变化。我们的结果描述了一种常见北美蛙类物种特定mRNA的组织分布及其对TH的敏感性，并支持该qPCR检测方法在识别调节TH作用的水生环境中化学物质存在方面的潜在用途。
