Profiling microRNAs in the testis during sexual maturation stages in Eriocheir sinensis.

MicroRNAs (miRNAs) have been implicated in several cellular processes of reproductive tissues through post-transcriptional regulation of protein coding genes. The presence of miRNAs, their expression patterns and processing machinery genes in different stages of testicular and ovarian cellular development have demonstrated the potential role of miRNAs in testicular and ovarian physiology. The Chinese mitten crab (Eriocheir sinensis) is one of the most important aquaculture species in China and has high commercial value as a food source. The molecular mechanisms underlying testis development in these and other crustaceans, which migrate to a new habitat to breed, remain poorly understood. We focus on the gonad of E. sinensis and systematically examined the expression profile of miRNAs in testes during sexual maturation stages using the Illumina Solexa sequencing technology. We found that the microRNA transcriptome exhibited dynamic expression during crab testis development. Subsequent bioinformatic analysis on both conserved and 15 novel miRNAs illustrated that some miRNAs demonstrated a tissue-specific expression pattern and were associated with target genes involved in reproductive function. Our study illustrates how detailed profiling of miRNA expression during stages of sexual maturation and in different tissues can lead to elucidate the role of miRNAs in regulating the development and differentiation of reproductive organs.