A review of the molecular mechanisms of monogonont rotifer reproduction

Abstract

Most animals use proteins, peptides, steroids, eicosanoids, or amino acid derivatives as chemical signals, along with receptors, secondary messengers, transduction systems, and transcription factors to finely control reproduction. Many protostomes have complex endocrine systems with vertebrate-like sex steroid receptors, but some are unresponsive to vertebrate sex steroids. Others are responsive to estrogen and testosterone, but the effects are mediated through non-estrogen receptor pathways. In this article, I review the pheromones that rotifers use to synchronize reproduction and rotifer response to waterborne vertebrate steroid hormones. I also describe the impact on rotifer reproduction of endocrine disruptors that mimic androgens and their antagonists. A fraction of the brachionid transcriptome is surveyed for candidates involved in endocrine signaling systems and genes are identified that are putatively involved in steroidogenesis and oocyte maturation. We use the new technique of RNAi in rotifers to selectively knock down gene expression and identify the functional roles of genes involved in the regulation of reproduction.