MicroRNAs (miRNAs) are small regulatory RNAs that are involved in many biological process in eukaryotes. They play a crucial role in modulating genetic expression of their targets, which makes them integral components of transcriptional regulatory networks. As sponges (phylum Porifera) are commonly considered the most basal metazoan, the in-depth capture of miRNAs from these organisms provides additional clues to the evolution of miRNA families in metazoans. Here, we identified the core proteins involved in the biogenesis of miRNAs, and obtained evidence for bona fide miRNA sequences for two marine sponges Stylissa carteri and Xestospongia testudinaria (11 and 19 respectively). Our analysis identified several miRNAs that are conserved amongst demosponges, and revealed that all of the novel miRNAs identified in these two species are specific to the class Demospongiae.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: We thank Annika Haywood, Feras Lafi and Holly Bream for extracting the RNA used for sequencing, as well as two anonymous reviewers for their invaluable suggestions. This project was supported by the King Abdullah University of Science and Technology (KAUST).