Sensillum development in the absence of cell division: The sensillum phenotype of the Drosophila mutant string☆

摘要

WehaveinvestigatedsensillumdevelopmentinDrosophilaembryoshomozygousformutationsinthelocusstring(stg).Intheseembryos,celldivisionisblockedfollowingblastodermformation.Thispermitsastudyofthedifferentiativefateofundividedprecursorcells,inparticularthosegivingrisetothelarvalsensoryorgans(sensilla).Ofthedifferentcellfatesnormallyrepresentedinthesensilla(i.e.,sensoryneuron,thecogencell,trichogencell,tormogencell,gliacell),onlythephenotypeofsensoryneuronsisexpressedmorphologicallyinstgembryos,suggestingthattheneuronalfatepredominatesoverthefatesofthenonneuronalaccessorycells.Consistentwiththisfinding,thePelement-lacZinsertionA1-2nd-29,whichisamarkerfortrichogenandtormogencellsinthewild-typeembryo,isnotexpressedinthebodywallofthestgembryo.Somesensillumprecursorcellsappeartoexpressamixedfateinstgmutants:Theyexpressantigens(recognizedbythemonoclonalantibodies22C10and21A6)whichinthewild-typeappearinseparatecells(sensoryneuronsandthecogencell,respectively).Thedifferentiationofundividedcellsinstgembryosisnotrestrictedtotheperipheralnervoussystem;inalltypesoftissuesanalyzedinthisstudy(e.g.,epidermis,intestine,muscle,CNS),precursorcellsexpresscharacteristicsnormallyexhibitedbytheirprogeny.