Characterization of miRNAs from hydrothermal vent shrimp Rimicaris exoculata

Deep-sea hydrothermal vent shrimp Rimicaris exoculata is a dominant species aggregating in vent fields along the Mid-Atlantic Ocean Ridge. MicroRNAs play important roles in life cycles of eukaryotes. However, little is known about miRNAs of vent animals. In the present study, a small RNA cDNA library from the muscle of R. exoculata was constructed and the miRNA sequencing was performed. The results indicated that a total of 7,983,331 raw reads were obtained, representing 569,354 unique sequences. Based on sequence analysis, R. exoculata contained 159 conserved miRNAs and 34 novel miRNAs. The conserved miRNAs included 54 families belonging to three different taxonomic units (bilaterian, protostomes and arthropods). The results also showed that miR-2001, a lost miRNA in crustaceans, existed in R. exoculata. Among the conserved miRNAs, iso-miRs were detected. Therefore, this study presented the first insight into the miRNAs of deep-sea hydrothermal vent animals.