01-P019 Small RNAs isolated from the ascidian Halocynthia roretzi embryos

Hox genes are essential transcription factors that establish segmental identity on the head–tail axis of all animals. Proper regulation of Hox gene expression and function is in part accomplished through the actions of a multitude of noncoding RNAs. One important class of noncoding RNA, the micro-RNAs (miRNAs), regulates gene activity through translational repression. The miR-10 family is highly conserved in sequence and genomic position among the anterior Hox genes of all bilaterians. Nevertheless, no study has examined miR-10s role in modulating Hox gene function in protostomes. Here, we examined the expression and function of the miR-10 family mainly in the fruit fly Drosophila melanogaster and the flour beetle Tribolium castaneum. We observed changes in the miR-10 expression and in the precursor arm from which the mature miRNA sequence derives. Our results suggest the function of miR-10 during the establishment of the head–tail axis among insects has diverged.