Testis-expressed cluster of microRNAs 959-964 controls spermatid differentiation in Drosophila

MicroRNAs are a wide class of [~]22 nt non-coding RNAs of metazoans capable of inhibiting target mRNAs translation by binding to partially complementary sites in their 3UTRs. Due to their regulatory potential, miRNAs are implicated in functioning of a broad range of biological pathways and processes. Here we investigate the functions of the miR-959-964 cluster expressed predominantly in testes of Drosophila melanogaster. The deletion of miR-959-964 resulted in male sterility due to the disturbance of the spermatid individualization process. Analysis of the transcriptome by microarray followed by luciferase reporter assay revealed didum, for, fdl and CG10512 as the targets of miR-959-964. Moreover, the deletion of miR-959-964 is accompanied by a decreased the expression of genes responsible for microtubule-based movement and spermatid differentiation. Thus, we suggest that miR-959-964 can control the process of spermatid individualization by direct and indirect modulating the expression of different components of the individualization process. In addition, we have shown that in comparison to other miRNAs, the rate of evolution of the testis-specific miR-959-964 cluster is unusually high, indicating its possible involvement in speciation via reproductive isolation.