title: Epithelial tube morphology is determined by the polarized growth and delivery of apical membrane.
abstract: Formation of tubes of the correct size and shape is essential for viability of most organisms, yet little is understood of the mechanisms controlling tube morphology. We identified a new allele of hairy in a mutagenesis screen and showed that hairy mutations cause branching and bulging of the normally unbranched salivary tube, in part through prolonged expression of huckebein (hkb). HKB controls polarized cell shape change and apical membrane growth during salivary cell invagination via two downstream target genes, crumbs (crb), a determinant of the apical membrane, and klarsicht (klar), which mediates microtubule-dependent organelle transport. In invaginating salivary cells, crb and klar mediate growth and delivery of apical membrane, respectively, thus regulating the size and shape of the salivary tube.
authors.affiliation: Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205, USA.
authors.forename: Monn Monn
authors.initials: MM
authors.lastname: Myat
authors.forename: Deborah J
authors.initials: DJ
authors.lastname: Andrew
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D002455:Cell Division; D002462:Cell Membrane / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000502:physiology; D004330:Drosophila; D029721:Drosophila Proteins / Q000502:physiology; D004848:Epithelium / Q000196:embryology*; D006720:Homozygote; D017403:In Situ Hybridization; D019476:Insect Proteins / Q000502:physiology; D008565:Membrane Proteins / Q000502:physiology; D026901:Membrane Transport Proteins; D008854:Microscopy, Electron; D016296:Mutagenesis; D009154:Mutation; D010641:Phenotype; D012097:Repressor Proteins / Q000502:physiology; D012469:Salivary Glands / Q000166:cytology* / Q000196:embryology* / Q000648:ultrastructure
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D019476:Insect Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D012097:Repressor Proteins; C087725:Hkb protein, Drosophila; C064360:crb protein, Drosophila; C489235:hairy protein, Drosophila; C401521:klar protein, Drosophila; C061841:hairy protein, insect