FoxB, a new and highly conserved key factor in arthropod dorsal–ventral (DV) limb patterning

Abstract

AbstractForkhead box (Fox) transcription factors evolved early in animal evolution and represent important components of conserved gene regulatory networks (GRNs) during animal development. Most of the researches concerning Fox genes, however, are on vertebrates and only a relatively low number of studies investigate Fox gene function in invertebrates. In addition to this shortcoming, the focus of attention is often restricted to a few well-characterized Fox genes such asFoxA(forkhead),FoxC(crocodile) andFoxQ2. Although arthropods represent the largest and most diverse animal group, most other Fox genes have not been investigated in detail, not even in the arthropod model speciesDrosophila melanogaster. In a general gene expression pattern screen for panarthropod Fox genes including the red flour beetleTribolium castaneum, the pill millipedeGlomeris marginata, the common house spiderParasteatoda tepidariorum, and the velvet wormEuperipatoides kanangrensis, we identified a Fox gene with a highly conserved expression pattern along the ventral ectoderm of arthropod and onychophoran limbs. Functional investigation ofFoxBinParasteatodareveals a hitherto unrecognized important function of FoxB upstream ofwingless(wg) anddecapentaplegic(dpp) in the GRN orchestrating dorsal–ventral limb patterning.