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. One of the significant advantages of next-gen sequencing over microarrays is the ability to perform expression profiling on species for which there is limited or no sequence information on record and potentially uncover novel small RNAs.
In the present study, a researchers from Zhejiang University constructed a small RNA cDNA library from the muscle of R. exoculata and perform miRNA sequencing. 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.