Spalt major controls the development of the notum and of wing hinge primordia of the Drosophila melanogaster wing imaginal disc

摘要

TheemDrosophila/emwingandthedorsalthoraxdevelopfromprimordiawithinthewingimaginaldisc.Hereweshowthatemspaltmajor(salm)/emisexpressedwithinthepresumptivedorsalbodywallprimordiumearlyinwingdiscdevelopmenttospecifynotumandwinghingetissue.Uponectopicemsalm/emexpression,dorsallylocatedsecondlegdisccellsdevelopnotumandwinghingetissueinsteadofsternopleuraltissue.Similarly,byemsalm/emover-expressionwithinthewingdisc,wingbladeformationissuppressedandamirror-imageduplicationofthenotumandwinghingeisformed.Inlargedorsalclones,whichlackemsalm/emanditsneighboringparalogueemspaltrelated(salr)/em,thecellsofthenotumprimordiumdonotgrow;thesedorsalcellsarenotspecifiedasnotum,hencenonotumoutgrowthdevelops.Theseresultssuggestthatthezincfingerfactorsencodedbytheemsalm/salr/emcomplexplayimportantrolesindefiningcellsoftheearlywingdiscasdorsalbodywallcells,whichdevelopintoalargedorsalbodywallterritoryandformmesonotumandsomewinghingetissue,andindelimitingthewingprimordium.Wealsofindthatemsalm/emactivityisdown-regulatedbyitsownproductandbythatofthePaxgeneemeyegone/em./p/div