title: Direct flight muscles in Drosophila develop from cells with characteristics of founders and depend on DWnt-2 for their correct patterning.
abstract: The direct flight muscles (DFMs) of Drosophila allow for the fine control of wing position necessary for flight. In DWnt-2 mutant flies, certain DFMs are either missing or fail to attach to the correct epithelial sites. Using a temperature-sensitive allele, we show that DWnt-2 activity is required only during pupation for correct DFM patterning. DWnt-2 is expressed in the epithelium of the wing hinge primordium during pupation. This expression is in the vicinity of the developing DFMs, as revealed by expression of the muscle founder cell-specific gene dumbfounded in DFM precursors. The observation that a gene necessary for embryonic founder cell function is expressed in the DFM precursors suggests that these cells may have a similar founder cell role. Although the expression pattern of DWnt-2 suggests that it could influence epithelial cells to differentiate into attachment sites for muscle, the expression of stripe, a transcription factor necessary for epithelial cells to adopt an attachment cell fate, is unaltered in the mutant. Ectopic expression of DWnt-2 in the wing hinge during pupation can also create defects in muscle patterning without alterations in stripe expression. We conclude that DWnt-2 promotes the correct patterning of DFMs through a mechanism that is independent of the attachment site differentiation initiated by stripe.
authors.affiliation: Department of Cell Biology, University of Alabama at Birmingham, Birmingham, AL 35294-0005, USA. kozopas@hotmail.com
authors.forename: Karen M
authors.initials: KM
authors.lastname: Kozopas
authors.forename: Roel
authors.initials: R
authors.lastname: Nusse
mesh_terms: D000818:Animals; D004268:DNA-Binding Proteins / Q000502:physiology; D029721:Drosophila Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D004331:Drosophila melanogaster / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D004475:Ectoderm / Q000502:physiology; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D005426:Flight, Animal; D018507:Gene Expression Regulation, Developmental; D007814:Larva; D008648:Mesoderm / Q000502:physiology; D008855:Microscopy, Electron, Scanning; D009024:Morphogenesis / Q000235:genetics; D009132:Muscles / Q000166:cytology*; D011518:Proto-Oncogene Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D011679:Pupa; D013234:Stem Cells / Q000166:cytology; D014157:Transcription Factors / Q000502:physiology; D014921:Wings, Animal / Q000254:growth & development* / Q000648:ultrastructure; D051154:Wnt2 Protein
chemical_list: D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D011518:Proto-Oncogene Proteins; D014157:Transcription Factors; D051154:Wnt2 Protein; C495251:Wnt2 protein, Drosophila; C096359:sr protein, Drosophila