Estrogen alters the profile of the transcriptome in river snail Bellamya aeruginosa

We evaluated the transcriptome dynamics of the freshwater river snail Bellamya aeruginosa exposed to 17β-estradiol (E2) using the Roche/454 GS-FLX platform. In total, 41,869 unigenes, with an average length of 586 bp, representing 36,181 contigs and 5,688 singlets were obtained. Among them, 18.08, 36.85, and 25.47 % matched sequences in the GenBank non-redundant nucleic acid database, non-redundant protein database, and Swiss protein database, respectively. Annotation of the unigenes with gene ontology, and then mapping them to biological pathways, revealed large groups of genes related to growth, development, reproduction, signal transduction, and defense mechanisms. Significant differences were found in gene expression in both liver and testicular tissues between control and E2-exposed organisms. These changes in gene expression will help in understanding the molecular mechanisms of the response to physiological stress in the river snail exposed to estrogen, and will facilitate research into biological processes and underlying physiological adaptations to xenoestrogen exposure in gastropods.