Reproductive health assessment and quantitative real-time PCR analysis of estrogen receptor mRNA expression in Mytilus galloprovincialis gametes

Many of the current procedures for territory management (see Horizon 2020) and marine organism reproductive health assessment are based upon receptor-mediated responses of target genes and are founded on the assumption that these responses accurately reflect exposure of endocrine disrupter that can be linked to different pathological effects. The role of estrogens and their functional mechanism of action in bivalves are therefore far from clear. Building on these observations, the aim of this study, in the frame work of an Italian National Research Project (PRIN 2010 – 2011), was to identify estrogen receptor genes (ER1 and ER2) and to quantify any changes in expression levels using the real-time quantitative PCR technique in response of marine bivalve, Mytilus galloprovincialis at different pollution degree areas. Using gametes obtained by mantle (gonad) tissue of mature bivalves we demonstrated, after sequencing and alignments, the presence of differentially expressed transcripts for ER1 and ER2, quantitative differences in male and female gamete gene expression and an increase in both gametes of ER levels in polluted area. The significance of these findings in terms of the utility of estrogen receptors as biomarkers of reproductive health assessment in bivalve species is discussed.