RNA-Seq-based transcriptome analysis of Korean rose bitterling (Rhodeus uyekii) exposed to synthetic estrogen 17-α-ethinylestradiol (EE2)

The potential impact of natural and synthetic estrogens on aquatic ecosystems has become a subject of great interest in recent years. One synthetic estrogen, 17-alpha-ethinylestradiol (EE2), is present in municipal sewage discharges and causes gonad alterations in various fish species. To understand the possible damage caused by EE2, male Rhodeus uyekii were exposed to 100 ng/L EE2 for 7 days. RNA-Seq was performed to assess the effects of EE2 on gene expression in hepatic and skin tissues. The analysis revealed that EE2 induced the expression of various genes, including sex hormone genes, anti-Mullerian hormone, vitellogenin, and estrogen receptor alpha; cancer genes, breast cancer anti-estrogen resistance protein 3, caveolin 2, and Smad2; and apoptotic genes, p53, Bcl-2, TNF-α, and WDR36. These results suggest that the synthetic estrogen EE2 disturbs the endocrine system and regulates both carcinogenic and apoptotic gene expressions in R. uyekii.