Ectopic gene expression and homeotic transformations in arthropods using recombinant Sindbis viruses

Background: The morphological diversity of arthropods makes them attractive subjects for studying the evolution of developmental mechanisms. Comparati ve analyses suggest that arthropod diversity has arisen largely as a result of changes in expression patterns of genes that control development, Direc t analysis of how a particular gene functions in a given species during dev elopment is hindered by the lack of broadly applicable techniques for manip ulating gene expression. Results: We report that the Arbovirus Sindbis can be used to deliver high l evels of gene expression in vivo in a number of non-host arthropod species without causing cytopathic effects in infected cells or impairing developme nt. Using recombinant Sindbis virus, we investigated the function of the ho meotic gene Ultrabithorax in the development of butterfly wings and beetle embryos, Ectopic Ultrabithorax expression in butterfly forewing imaginal di scs was sufficient to cause the transformation of characteristic forewing p roperties in the adult, including scale morphology and pigmentation, to tho se of the hindwing, Expression of Ultrabithorax in beetle embryos outside o f its endogenous expression domain affected normal development of the body wall cuticle and appendages, Conclusions: The homeotic genes have long been thought to play an important role in the diversification of arthropod appendages, Using recombinant Sin dbis virus, we were able to investigate homeotic gene function in non-model arthropod species. We found that Ultrabithorax is sufficient to confer hin dwing identity in butterflies and alter normal development of anterior stru ctures in beetles. Recombinant Sindbis virus has broad potential as a tool for analyzing how the function of developmental genes has changed during th e diversification of arthropods.