Phylogenetics and Functions of the Double-Stranded RNA-Binding Motif: A Genomic Survey

The double-stranded RNA-binding motif (dsRBM) is found in a diverse array of proteins that regulate gene expression in many organisms. We surveyed all known and predicted protein sequences from several organisms for the presence of the dsRBM. Among the major taxa sampled, only archebacteria lacked this motif. Plants and viruses appear to exploit the motif in proteins not found in animals. For five genomes (a bacterium, yeast, nematode, fly, and human), the proteins were annotated and examined in detail. The number of dsRBM-containing proteins increased along this series, as did the incidence of multiple dsRBMs. The dsRBM-containing proteins of the five type species are grouped into 21 families according to their similarities in domain and overall sequences, and the presence of other domains. These data provide a basis for understanding the evolution of the dsRBM, as well as the functions of proteins that contain it.