title: Integration of contractile forces during tissue invagination.
abstract: Contractile forces generated by the actomyosin cytoskeleton within individual cells collectively generate tissue-level force during epithelial morphogenesis. During Drosophila mesoderm invagination, pulsed actomyosin meshwork contractions and a ratchet-like stabilization of cell shape drive apical constriction. Here, we investigate how contractile forces are integrated across the tissue. Reducing adherens junction (AJ) levels or ablating actomyosin meshworks causes tissue-wide epithelial tears, which release tension that is predominantly oriented along the anterior-posterior (a-p) embryonic axis. Epithelial tears allow cells normally elongated along the a-p axis to constrict isotropically, which suggests that apical constriction generates anisotropic epithelial tension that feeds back to control cell shape. Epithelial tension requires the transcription factor Twist, which stabilizes apical myosin II, promoting the formation of a supracellular actomyosin meshwork in which radial actomyosin fibers are joined end-to-end at spot AJs. Thus, pulsed actomyosin contractions require a supracellular, tensile meshwork to transmit cellular forces to the tissue level during morphogenesis.
authors.affiliation: Department of Molecular Biology, Howard Hughes Medical Institute, Princeton University, Princeton, NJ 08544, USA.
authors.forename: Adam C
authors.initials: AC
authors.lastname: Martin
authors.forename: Michael
authors.initials: M
authors.lastname: Gelbart
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Fernandez-Gonzalez
authors.forename: Matthias
authors.initials: M
authors.lastname: Kaschube
authors.forename: Eric F
authors.initials: EF
authors.lastname: Wieschaus
mesh_terms: D000205:Actomyosin / Q000235:genetics / Q000378:metabolism*; D022005:Adherens Junctions / Q000378:metabolism; D000818:Animals; D030801:Animals, Genetically Modified; D016880:Anisotropy; D015415:Biomarkers / Q000378:metabolism; D002448:Cell Adhesion / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D048430:Cell Shape; D003599:Cytoskeleton / Q000378:metabolism / Q000648:ultrastructure; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D004848:Epithelium / Q000033:anatomy & histology / Q000502:physiology; D009024:Morphogenesis / Q000502:physiology*; D024462:Myosin Type II / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D000071250:Snail Family Transcription Factors; D013314:Stress, Mechanical; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D051879:Twist-Related Protein 1 / Q000235:genetics / Q000378:metabolism
chemical_list: D015415:Biomarkers; D029721:Drosophila Proteins; D011993:Recombinant Fusion Proteins; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors; D051879:Twist-Related Protein 1; C000604451:sna protein, Drosophila; D000205:Actomyosin; D024462:Myosin Type II