Department of Ecology and Animal Biology, University of Vigo, 36310, Vigo, Spain; Marine Research Centre, University of Vigo (CIM-UVIGO), Isla de Toralla, Vigo, Spain; Department of Biochemistry, Genetics and Immunology, University of Vigo, 36310, Vigo, Spain.
Department of Ecology and Animal Biology, University of Vigo, 36310, Vigo, Spain; Centro Oceanográfico de Vigo, Instituto Español de Oceanografía, 36390, Vigo, Spain.
Mar Environ Res. 2021 Jun;168:105315. doi: 10.1016/j.marenvres.2021.105315. Epub 2021 Mar 26.
Vitellogenin (Vtg), a large multidomain protein precursor of egg-yolk proteins, is used as an endocrine disruption biomarker in fish, and in the last decades, its use has been extended to invertebrates like mollusks. However, it remains unclear whether invertebrate endocrine system produces Vtg in response to estrogens, like it occurs in oviparous vertebrates. In a previous study, no evidence of induction of Vtg expression at protein level was found in gonads of the marine mussel Mytilus galloprovincialis after exposure to the estrogenic chemical 17α-ethinylestradiol (EE2). In the present follow-up study, it was investigated whether there is any effect of EE2 on Vtg abundance at transcriptional level in M. galloprovincialis gonads. To this aim, RT-qPCR analysis targeting three different domains of Vtg transcript was performed on gonads of mussels that were exposed either 4 or 24 days to 100 ng/L EE2. In addition, several reference genes were analysed and a selection of these for potential use in further RT-qPCR analyses on mussel male and female gonads is provided. Results showed higher expression in females than in males for the three analysed Vtg domains, and no evidence of Vtg mRNA induction due to EE2 either in females or males. The present results, together with those obtained from previous analysis at protein level, support that Vtg is not an adequate biomarker for xenoestrogenicity in marine mussels. Additionally, nucleotide sequences of Vtg transcripts of three closely-related species from Mytilus edulis complex (M. galloprovincialis, M. edulis and M. trossulus) are provided and compared with Vtg sequences from other mollusk species to assess the level of conservation and evolutionary relationships among species.
卵黄蛋白原（Vtg）是一种大型多功能蛋白前体，是鱼类内分泌干扰生物标志物，在过去几十年中，其应用范围已扩展到软体动物等无脊椎动物。然而，目前尚不清楚无脊椎动物的内分泌系统是否像卵生脊椎动物那样，对雌激素产生 Vtg。在之前的一项研究中，在暴露于雌激素 17α-乙炔基雌二醇（EE2）后，在海洋贻贝 Mytilus galloprovincialis 的性腺中未发现 Vtg 蛋白水平表达诱导的证据。在本后续研究中，研究了 EE2 是否对 M. galloprovincialis 性腺中 Vtg 丰度在转录水平上有任何影响。为此，对暴露于 100ng/L EE2 4 或 24 天的贻贝性腺进行了针对 Vtg 转录物三个不同结构域的 RT-qPCR 分析。此外，还分析了几个参考基因，并提供了这些基因中一些用于贻贝雄性和雌性性腺进一步 RT-qPCR 分析的选择。结果表明，在三个分析的 Vtg 结构域中，雌性的表达高于雄性，并且在雌性或雄性中均未发现由于 EE2 导致 Vtg mRNA 诱导。这些结果与之前在蛋白质水平上获得的结果一起表明，Vtg 不是海洋贻贝中环境雌激素的合适生物标志物。此外，还提供了来自 Mytilus edulis 复合体的三个密切相关物种（M. galloprovincialis、M. edulis 和 M. trossulus）的 Vtg 转录物的核苷酸序列，并与其他软体动物物种的 Vtg 序列进行了比较，以评估物种之间的保守程度和进化关系。
