Abstract
RNA-mediated interference (RNAi) provides a rapid and potent approach for analyzing gene function in vivo. The conventional RNAi technique is performed by microinjection of double-stranded RNA (dsRNA) into syncytial blastoderm embryos (embryonic RNAi). While the embryonic RNAi method is efficient for analyses of embryogenesis, it is inappropriate for analyses of postembryonic development. To circumvent this problem, larval RNAi by the injection of dsRNA into the larval body cavity had been reported using Tribolium castaneum. In order to demonstrate the general utility of the larval RNAi method in non-model insects, we used the evolutionary conserved homeobox genes required for appendage formation, Distal-less (Dll) and aristaless (al), to affirm their function in adult development of the ladybird beetle, Harmonia axyridis. The injection of dsRNA for Harmonia Dll (Ha-Dll) and al (Ha-al) into the early stage of last instar larvae efficiently induced adult morphological defects that mimicked those of known loss-of-function phenotypes for these genes. Surprisingly, these adult defects by larval RNAi were induced with a 100% penetrance. We conclude that larval RNAi is extremely efficient for the analysis of adult development in Harmonia and that larval RNAi will become a powerful new tool for analyzing postembryonic development at a molecular level, particularly in non-model insects.
© 2005 by Japan Academic Association for Copyright Clearance (Except in the USA), Copyright Clearance Center, Inc. (In the USA)
