title: Uncoupling apical constriction from tissue invagination.
abstract: Apical constriction is a widely utilized cell shape change linked to folding, bending and invagination of polarized epithelia. It remains unclear how apical constriction is regulated spatiotemporally during tissue invagination and how this cellular process contributes to tube formation in different developmental contexts. UsingDrosophilasalivary gland (SG) invagination as a model, we show that regulation offolded gastrulationexpression by the Fork head transcription factor is required for apicomedial accumulation of Rho kinase and non-muscle myosin II, which coordinate apical constriction. We demonstrate that neither loss of spatially coordinated apical constriction nor its complete blockage prevent internalization and tube formation, although such manipulations affect the geometry of invagination. When apical constriction is disrupted, compressing force generated by a tissue-level myosin cable contributes to SG invagination. We demonstrate that fully elongated polarized SGs can form outside the embryo, suggesting that tube formation and elongation are intrinsic properties of the SG.
authors.affiliation: Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, United States.
authors.forename: SeYeon
authors.identifier: 0000-0002-5493-6424
authors.initials: S
authors.lastname: Chung
authors.affiliation: Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, United States.
authors.forename: Sangjoon
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, United States.
authors.forename: Deborah J
authors.identifier: 0000-0003-1051-6935
authors.initials: DJ
authors.lastname: Andrew
mesh_terms: D000818:Animals; D004330:Drosophila / Q000196:embryology*; D009024:Morphogenesis; D024462:Myosin Type II / Q000378:metabolism; D012469:Salivary Glands / Q000196:embryology*
chemical_list: D024462:Myosin Type II
keywords: D. melanogaster; Drosophila; apical constriction; cell biology; developmental biology; fog; fork head; myosin; salivary gland; stem cells