Expression of sf1 and dax-1 are regulated by thyroid hormones and androgens during Silurana tropicalis early development
Expression of sf1 and dax-1 are regulated by thyroid hormones and androgens during Silurana tropicalis early development
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DOI：
10.1016/j.ygcen.2017.10.017
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发表时间：
2018-04-01
影响因子：
2.7
通讯作者：
Langlois, Valerie S.
中科院分区：
文献类型：
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作者：
Campbell, Diana E. K.;Langlois, Valerie S.
甲状腺激素(TH)和雄激素已被证明与性发育有关；然而，关于TH相关和雄激素在性别决定中的作用，人们知之甚少。我们首次建立了三个性别决定基因(SF1、DAX-1和Sox9)在热带西爪蛙胚胎发育过程中的表达谱。在胚胎转录开始表明母体移植的时期之前，胚胎中就检测到了SF1和Sox9的转录，而DAX-1的转录直到发育后期才被检测到。为了研究TH状态是否影响胚胎中性别决定基因的表达，将胚胎暴露在碘酸(IOP)、甲状腺素(T4)或三碘甲状腺原氨酸(T3)的共同处理下96h，TH受体和脱碘酶的表达谱反映了IOP对外周脱碘酶活性的抑制和T3对脱碘酶活性的恢复。相应地，TH水平的升高显著增加了SF1和DAX-1在热带血吸虫胚胎中的表达。进一步支持TH介导的调控，在热带链霉菌以及啮齿动物和鱼类模型中对性别决定基因的假定启动子区的转录因子结合位点的存在和频率的检测也在SF1和DAX-1的假定启动子区域发现了TH基序。总而言之，这些发现表明，早在胚胎发育时期就采取的行动可能会影响青蛙的性腺命运。TH和雄激素串扰与类固醇相关基因表达调控的机制也进行了研究。(C)2017 Elsevier Inc.保留所有权利。
Thyroid hormones (THs) and androgens have been shown to be extensively involved in sexual development; however, relatively little is known with regard to TH-related and androgenic actions in sex determination. We first established expression profiles of three sex-determining genes (sf1, dax-1, and sox9) during the embryonic development of Western clawed frogs (Silurana tropicalis). Transcripts of sf1 and sox9 were detected in embryos before the period in which embryonic transcription commences indicating maternal transfer, whereas dax-1 transcripts were not detected until later in development. To examine whether TH status affects sex-determining gene expression in embryonic S. tropicalis, embryos were exposed to co-treatments of iopanoic acid (IOP), thyroxine (T4), or triiodothyronine (T3) for 96 h. Expression profiles of TH receptors and deiodinases reflect inhibition of peripheral deiodinase activity by IOP and recovery by T3. Relevantly, elevated TH levels significantly increased the expression of sf1 and dax-1 in embryonic S. tropicalis. Further supporting TH-mediated regulation, examination of the presence and frequency of transcription factor binding sites in the putative promoter regions of sex determining genes in S. tropicalis and rodent and fish models using in silico analysis also identified TH motifs in the putative promoter regions of sf1 and dax-1. Together these findings advocate that TH actions as early as the period of embryogenesis may affect gonadal fate in frogs. Mechanisms of TH and androgenic crosstalk in relation to the regulation of steroid-related gene expression were also investigated. (C) 2017 Elsevier Inc. All rights reserved.