Functional analysis of microRNA activity in Brugia malayi

•Insertion of a recognition site for a microRNA (miRNA) reduces reporter gene expression in Brugia malayi.•Mutation of the seed and 5′ end sequences of the miRNA recognition site partially restore expression.•miRNA target prediction algorithms developed for other organisms can predict miRNA targets in B. malayi.•Transient transfection of B. malayi embryos can be used to functionally assay miRNA recognition sites.

The complement of the Brugia malayi microRNA-71 was inserted into the 3′ untranslated region of a reporter plasmid, resulting in a decrease in reporter activity. Mutation of the seed sequence restored activity. Insertion of the 3′ untranslated regions from two algorithm-predicted putative target genes into the reporter resulted in a similar decrease in activity; mutation of the predicted target sequences restored activity. These experiments demonstrate that B. malayi microRNA targets may be predicted using current algorithms and describe a functional assay to confirm predicted targets.