Characterization of anillin mutants reveals essential roles in septin localization and plasma membrane integrity.
Anillin is a conserved component of the contractile ring that is essential for cytokinesis, and physically interacts with three conserved cleavage furrow proteins, F-actin, myosin II and septins in biochemical assays. We demonstrate that the Drosophila scraps gene, identified as a gene involved in cellularization, encodes Anillin. We characterize defects in cellularization, pole cell formation and cytokinesis in a series of maternal effect and zygotic anillin alleles. Mutations that result in amino acid changes in the C-terminal PH domain of Anillin cause defects in septin recruitment to the furrow canal and contractile ring. These mutations also strongly perturb cellularization, altering the timing and rate of furrow ingression. They cause dramatic vesiculation of new plasma membranes, and destabilize the stalk of cytoplasm that normally connects gastrulating cells to the yolk mass. A mutation closer to the N terminus blocks separation of pole cells with less effect on cellularization, highlighting mechanistic differences between contractile processes. Cumulatively, our data point to an important role for Anillin in scaffolding cleavage furrow components, directly stabilizing intracellular bridges, and indirectly stabilizing newly deposited plasma membrane during cellularization.
Field
Christine M
CM
Department of Systems Biology, Harvard Medical School, Boston MA 02115, USA. cfield@hms.harvard.edu
Coughlin
Margaret
M
Doberstein
Steve
S
Marty
Thomas
T
Sullivan
William
W
D000199:Actins / Q000378:metabolism; D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D003285:Contractile Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D048749:Cytokinesis; D003598:Cytoskeletal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D016415:Sequence Alignment; D015053:Zygote / Q000737:chemistry / Q000378:metabolism
D000199:Actins; D003285:Contractile Proteins; D003598:Cytoskeletal Proteins; D029721:Drosophila Proteins; C095886:anillin