title: Drosophilachemmutations disrupt epithelial polarity in Drosophila embryos.
abstract: Drosophila embryogenesis has proven to be an extremely powerful system for developmental gene discovery and characterization. We isolated five new EMS-induced alleles that do not complement thel(3R)5G83lethal line isolated in the Nüsslein-Volhard and Wieschaus screens. We have named this locuschem. Lethality of the new alleles as homozygous zygotic mutants is not completely penetrant, and they have an extended phenocritical period. Like the original allele, a fraction of mutant embryos die with cuticular defects, notably head involution and dorsal closure defects. Embryonic defects are much more extreme in germline clones, where the majority of mutant embryos die during embryogenesis and do not form cuticle, implying a strongchemmaternal contribution.chemmutations genetically interact with mutations in cytoskeletal genes (arm) and with mutations in the epithelial polarity genescoracle, crumbs,andyurt.chemmutants dorsal open defects are similar to those present inyurtmutants, and, likewise, they have epithelial polarity defects.chem1andchem3mutations suppressyurt3, andchem3mutants suppresscrumbs1mutations. In contrast,chem1andcoracle2mutations enhance each other. Compared to controls, inchemmutants in embryonic lateral epithelia Crumbs expression is mislocalized and reduced, Coracle is increased and mislocalized basally at embryonic stages 13-14, then reduced at stage 16. Arm expression has a similar pattern but levels are reduced.
authors.affiliation: Developmental Neurobiology and Neurophysiology, Instituto de Neurobiología, Universidad Nacional Autónoma de México , Querétaro , Querétaro , México.
authors.forename: José M
authors.initials: JM
authors.lastname: Zamudio-Arroyo
authors.affiliation: Developmental Neurobiology and Neurophysiology, Instituto de Neurobiología, Universidad Nacional Autónoma de México , Querétaro , Querétaro , México.
authors.forename: Juan R
authors.initials: JR
authors.lastname: Riesgo-Escovar
keywords: Cell polarity; Dorsal closure; Epithelial cell; Head involution