Neuronal Transcriptome Analysis of a Widely Recognised Molluscan Model Organism Highlights the Absence of Key Proteins Involved in the De Novo Synthesis and Receptor-Mediation of Sex Steroids in Vertebrates

Over the last ten years, interpretation of presence vertebrate sex steroids in molluscs has changed dramatically. Evidence been accumulating that CYP11A and CYP19A genes (encoding cholesterol side-chain cleavage enzyme aromatase), are crucial for biosynthesis vertebrates, as well key functional steroid receptors, missing molluscan genomes. To provide further evidence, we sequenced whole transcriptome central nervous system great pond snail (Lymnaea stagnalis) screened it sequences homologous to those used generally accepted steroidogenesis pathway known receptor-related (such CYP11A, CYP19A, 3β-HSD, nPR, nAR). Our screening confirmed absence several essential accomplish a full similar vertebrates. There was also no evidence nuclear receptors. findings support contention endocrinology differs from well-characterized endocrine system.