dFmr1 Plays Roles in Small RNA Pathways of Drosophila melanogaster

Fragile-X syndrome is the most common form of inherited mental retardation accompanied by other phenotypes, including macroorchidism. The disorder originates with mutations in the gene coding for the FMRP protein, which, with its paralogs and , constitute a well-conserved family of RNA-binding proteins. is a good model for the syndrome because it has a unique gene: . Recently, in addition to its confirmed role in the miRNA pathway, a function for dFmr1 in the piRNA pathway, operating in gonads, has been established. In this review we report a summary of the piRNA pathways occurring in gonads with a special emphasis on the relationship between the genes and the system; we also analyze the roles of dFmr1 in the gonads, exploring their genetic and biochemical interactions to reveal some unexpected connections.