Dicer-1 is a key enzyme in the regulation of oogenesis in panoistic ovaries

Background information In insects, the action of microRNAs (miRNAs) on oogenesis has been explored only in dipterans, which possess meroistic ovaries, a highly modified ovarian type. Here we study miRNA function in the most primitive, panoistic type of ovaries using the phylogenetically basal insect Blattella germanica (Dictyoptera, Blattellidae) as model. Results Dicer-1 (Dcr1), a key enzyme in miRNA biogenesis, was depleted using RNAi. Females treated with double-stranded RNA targeting Dicer-1, exhibited deep alterations in oocyte development; among them, the follicular epithelia of the basal oocytes did not develop, thus resulting in sterile females. Conclusions These effects derived from the absence of Dicer-1 suggest that miRNAs are crucial for the regulation of oogenesis in panoistic ovaries, the most primitive insect ovarian type.