The roles of wingless and decapentaplegic in axis and appendage development in the red flour beetle, Tribolium castaneum

• Published in: Developmental biology 2006-06, Vol.294 (2), p.391-405
• Main Authors: Ober, Karen A., Jockusch, Elizabeth L.
• Format: Article
• Language: English
• Subjects: Animals; Appendage development; Axis patterning; Body Patterning; Decapentaplegic; Drosophila melanogaster; Drosophila Proteins - genetics; Drosophila Proteins - metabolism; Embryo, Nonmammalian - anatomy & histology; Embryo, Nonmammalian - physiology; Gene Expression Regulation, Developmental; In Situ Hybridization; Insect Proteins - genetics; Insect Proteins - metabolism; Morphogenesis; Phenotype; Proto-Oncogene Proteins - genetics; Proto-Oncogene Proteins - metabolism; Repressor Proteins - genetics; Repressor Proteins - metabolism; RNA Interference; Signal Transduction - physiology; Tribolium - anatomy & histology; Tribolium - embryology; Tribolium - genetics; Tribolium castaneum; Wingless; Wnt Proteins
• ISSN: 0012-1606; 1095-564X
• DOI: 10.1016/j.ydbio.2006.02.053

Axis patterning and appendage development have been well studied in Drosophila melanogaster, a species in which both limb and segment morphogenesis are derived. In Drosophila, positional information from genes important in anteroposterior and dorsoventral axis formation, including wingless ( wg) and decapentaplegic ( dpp), is required for allocating and patterning the appendage primordia. We used RNA interference to characterize the functions of wg and dpp in the red flour beetle, Tribolium castaneum, which retains more ancestral modes of limb and segment morphogenesis. We also characterized the expression of potential targets of the WG and DPP signaling pathways in these embryos. Tribolium embryos in which dpp had been downregulated had defects in the dorsalmost body wall, but did not appear to have been globally repatterned and had normal appendages. Downregulation of wg led to the loss of segment boundaries, gnathal and thoracic appendages, and lateral head lobes, and to changes in the expression of dpp, Distal-less, and Engrailed. The functions of wg varied along both the anteroposterior and dorsoventral axes of the embryo. Phylogenetic comparisons indicate that the role of WNT signaling in segment boundary formation is evolutionarily old, but that its role in appendage allocation originated in the common ancestor of holometabolous insects.