Logo of jcellbiolHomeThe Rockefeller University PressEditorsContactInstructions for AuthorsThis issue
J Cell Biol. 1995 Jun 2; 129(6): 1575–1588.
PMCID: PMC2291172

The 95F unconventional myosin is required for proper organization of the Drosophila syncytial blastoderm


The 95F myosin, a class VI unconventional myosin, associates with particles in the cytoplasm of the Drosophila syncytial blastoderm and is required for the ATP- and F-actin-dependent translocation of these particles. The particles undergo a cell cycle-dependent redistribution from domains that surround each nucleus in interphase to transient membrane invaginations that provide a barrier between adjacent spindles during mitosis. When 95F myosin function is inhibited by antibody injection, profound defects in syncytial blastoderm organization occur. This disorganization is seen as aberrant nuclear morphology and position and is suggestive of failures in cytoskeletal function. Nuclear defects correlate with gross defects in the actin cytoskeleton, including indistinct actin caps and furrows, missing actin structures, abnormal spacing of caps, and abnormally spaced furrows. Three- dimensional examination of embryos injected with anti-95F myosin antibody reveals that actin furrows do not invaginate as deeply into the embryo as do normal furrows. These furrows do not separate adjacent mitoses, since microtubules cross over them. These inappropriate microtubule interactions lead to aberrant nuclear divisions and to the nuclear defects observed. We propose that 95F myosin function is required to generate normal actin-based transient membrane furrows. The motor activity of 95F myosin itself and/or components within the particles transported to the furrows by 95F myosin may be required for normal furrows to form.

Full Text

The Full Text of this article is available as a PDF (5.1M).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Adams RJ, Pollard TD. Propulsion of organelles isolated from Acanthamoeba along actin filaments by myosin-I. Nature. 1986 Aug 21;322(6081):754–756. [PubMed]
  • Agard DA, Hiraoka Y, Shaw P, Sedat JW. Fluorescence microscopy in three dimensions. Methods Cell Biol. 1989;30:353–377. [PubMed]
  • Baines IC, Brzeska H, Korn ED. Differential localization of Acanthamoeba myosin I isoforms. J Cell Biol. 1992 Dec;119(5):1193–1203. [PMC free article] [PubMed]
  • Bement WM, Mooseker MS. Molecular motors. Keeping out the rain. Nature. 1993 Oct 28;365(6449):785–786. [PubMed]
  • Bement WM, Hasson T, Wirth JA, Cheney RE, Mooseker MS. Identification and overlapping expression of multiple unconventional myosin genes in vertebrate cell types. Proc Natl Acad Sci U S A. 1994 Jul 5;91(14):6549–6553. [PMC free article] [PubMed]
  • Cheney RE, Mooseker MS. Unconventional myosins. Curr Opin Cell Biol. 1992 Feb;4(1):27–35. [PubMed]
  • Cheney RE, O'Shea MK, Heuser JE, Coelho MV, Wolenski JS, Espreafico EM, Forscher P, Larson RE, Mooseker MS. Brain myosin-V is a two-headed unconventional myosin with motor activity. Cell. 1993 Oct 8;75(1):13–23. [PubMed]
  • Cheney RE, Riley MA, Mooseker MS. Phylogenetic analysis of the myosin superfamily. Cell Motil Cytoskeleton. 1993;24(4):215–223. [PubMed]
  • Collins K, Sellers JR, Matsudaira P. Calmodulin dissociation regulates brush border myosin I (110-kD-calmodulin) mechanochemical activity in vitro. J Cell Biol. 1990 Apr;110(4):1137–1147. [PMC free article] [PubMed]
  • De Lozanne A, Spudich JA. Disruption of the Dictyostelium myosin heavy chain gene by homologous recombination. Science. 1987 May 29;236(4805):1086–1091. [PubMed]
  • Doberstein SK, Baines IC, Wiegand G, Korn ED, Pollard TD. Inhibition of contractile vacuole function in vivo by antibodies against myosin-I. Nature. 1993 Oct 28;365(6449):841–843. [PubMed]
  • Fath KR, Burgess DR. Golgi-derived vesicles from developing epithelial cells bind actin filaments and possess myosin-I as a cytoplasmically oriented peripheral membrane protein. J Cell Biol. 1993 Jan;120(1):117–127. [PMC free article] [PubMed]
  • Fath KR, Trimbur GM, Burgess DR. Molecular motors are differentially distributed on Golgi membranes from polarized epithelial cells. J Cell Biol. 1994 Aug;126(3):661–675. [PMC free article] [PubMed]
  • Foe VE, Alberts BM. Studies of nuclear and cytoplasmic behaviour during the five mitotic cycles that precede gastrulation in Drosophila embryogenesis. J Cell Sci. 1983 May;61:31–70. [PubMed]
  • Fukui Y, Lynch TJ, Brzeska H, Korn ED. Myosin I is located at the leading edges of locomoting Dictyostelium amoebae. Nature. 1989 Sep 28;341(6240):328–331. [PubMed]
  • Hafen E, Kuroiwa A, Gehring WJ. Spatial distribution of transcripts from the segmentation gene fushi tarazu during Drosophila embryonic development. Cell. 1984 Jul;37(3):833–841. [PubMed]
  • Hasson T, Mooseker MS. Porcine myosin-VI: characterization of a new mammalian unconventional myosin. J Cell Biol. 1994 Oct;127(2):425–440. [PMC free article] [PubMed]
  • Huxley HE. The mechanism of muscular contraction. Science. 1969 Jun 20;164(3886):1356–1365. [PubMed]
  • Joshi S, Miller MI. Maximum a posteriori estimation with Good's roughness for three-dimensional optical-sectioning microscopy. J Opt Soc Am A. 1993 May;10(5):1078–1085. [PubMed]
  • Karess RE, Chang XJ, Edwards KA, Kulkarni S, Aguilera I, Kiehart DP. The regulatory light chain of nonmuscle myosin is encoded by spaghetti-squash, a gene required for cytokinesis in Drosophila. Cell. 1991 Jun 28;65(7):1177–1189. [PubMed]
  • Karr TL, Alberts BM. Organization of the cytoskeleton in early Drosophila embryos. J Cell Biol. 1986 Apr;102(4):1494–1509. [PMC free article] [PubMed]
  • Kellerman KA, Miller KG. An unconventional myosin heavy chain gene from Drosophila melanogaster. J Cell Biol. 1992 Nov;119(4):823–834. [PMC free article] [PubMed]
  • Kellogg DR, Mitchison TJ, Alberts BM. Behaviour of microtubules and actin filaments in living Drosophila embryos. Development. 1988 Aug;103(4):675–686. [PubMed]
  • Knecht DA, Loomis WF. Antisense RNA inactivation of myosin heavy chain gene expression in Dictyostelium discoideum. Science. 1987 May 29;236(4805):1081–1086. [PubMed]
  • Mermall V, McNally JG, Miller KG. Transport of cytoplasmic particles catalysed by an unconventional myosin in living Drosophila embryos. Nature. 1994 Jun 16;369(6481):560–562. [PubMed]
  • Miller KG, Field CM, Alberts BM. Actin-binding proteins from Drosophila embryos: a complex network of interacting proteins detected by F-actin affinity chromatography. J Cell Biol. 1989 Dec;109(6 Pt 1):2963–2975. [PMC free article] [PubMed]
  • Minden JS, Agard DA, Sedat JW, Alberts BM. Direct cell lineage analysis in Drosophila melanogaster by time-lapse, three-dimensional optical microscopy of living embryos. J Cell Biol. 1989 Aug;109(2):505–516. [PMC free article] [PubMed]
  • Miyata H, Bowers B, Korn ED. Plasma membrane association of Acanthamoeba myosin I. J Cell Biol. 1989 Oct;109(4 Pt 1):1519–1528. [PMC free article] [PubMed]
  • Pasternak C, Spudich JA, Elson EL. Capping of surface receptors and concomitant cortical tension are generated by conventional myosin. Nature. 1989 Oct 12;341(6242):549–551. [PubMed]
  • Peters DJ, Knecht DA, Loomis WF, De Lozanne A, Spudich J, Van Haastert PJ. Signal transduction, chemotaxis, and cell aggregation in Dictyostelium discoideum cells without myosin heavy chain. Dev Biol. 1988 Jul;128(1):158–163. [PubMed]
  • Pollard TD, Cooper JA. Actin and actin-binding proteins. A critical evaluation of mechanisms and functions. Annu Rev Biochem. 1986;55:987–1035. [PubMed]
  • Pollard TD, Doberstein SK, Zot HG. Myosin-I. Annu Rev Physiol. 1991;53:653–681. [PubMed]
  • Postner MA, Miller KG, Wieschaus EF. Maternal effect mutations of the sponge locus affect actin cytoskeletal rearrangements in Drosophila melanogaster embryos. J Cell Biol. 1992 Dec;119(5):1205–1218. [PMC free article] [PubMed]
  • Raff JW, Glover DM. Centrosomes, and not nuclei, initiate pole cell formation in Drosophila embryos. Cell. 1989 May 19;57(4):611–619. [PubMed]
  • Sullivan W, Minden JS, Alberts BM. daughterless-abo-like, a Drosophila maternal-effect mutation that exhibits abnormal centrosome separation during the late blastoderm divisions. Development. 1990 Oct;110(2):311–323. [PubMed]
  • Sullivan W, Daily DR, Fogarty P, Yook KJ, Pimpinelli S. Delays in anaphase initiation occur in individual nuclei of the syncytial Drosophila embryo. Mol Biol Cell. 1993 Sep;4(9):885–896. [PMC free article] [PubMed]
  • Sullivan W, Fogarty P, Theurkauf W. Mutations affecting the cytoskeletal organization of syncytial Drosophila embryos. Development. 1993 Aug;118(4):1245–1254. [PubMed]
  • Tan JL, Ravid S, Spudich JA. Control of nonmuscle myosins by phosphorylation. Annu Rev Biochem. 1992;61:721–759. [PubMed]
  • Titus MA, Wessels D, Spudich JA, Soll D. The unconventional myosin encoded by the myoA gene plays a role in Dictyostelium motility. Mol Biol Cell. 1993 Feb;4(2):233–246. [PMC free article] [PubMed]
  • Wagner MC, Barylko B, Albanesi JP. Tissue distribution and subcellular localization of mammalian myosin I. J Cell Biol. 1992 Oct;119(1):163–170. [PMC free article] [PubMed]
  • Warn RM, Flegg L, Warn A. An investigation of microtubule organization and functions in living Drosophila embryos by injection of a fluorescently labeled antibody against tyrosinated alpha-tubulin. J Cell Biol. 1987 Oct;105(4):1721–1730. [PMC free article] [PubMed]
  • Weeds A. Actin-binding proteins--regulators of cell architecture and motility. Nature. 1982 Apr 29;296(5860):811–816. [PubMed]
  • Wessels D, Soll DR, Knecht D, Loomis WF, De Lozanne A, Spudich J. Cell motility and chemotaxis in Dictyostelium amebae lacking myosin heavy chain. Dev Biol. 1988 Jul;128(1):164–177. [PubMed]
  • Wessels D, Murray J, Jung G, Hammer JA, 3rd, Soll DR. Myosin IB null mutants of Dictyostelium exhibit abnormalities in motility. Cell Motil Cytoskeleton. 1991;20(4):301–315. [PubMed]
  • Wolenski JS, Hayden SM, Forscher P, Mooseker MS. Calcium-calmodulin and regulation of brush border myosin-I MgATPase and mechanochemistry. J Cell Biol. 1993 Aug;122(3):613–621. [PMC free article] [PubMed]
  • Yasuda GK, Baker J, Schubiger G. Independent roles of centrosomes and DNA in organizing the Drosophila cytoskeleton. Development. 1991 Feb;111(2):379–391. [PubMed]
  • Young PE, Pesacreta TC, Kiehart DP. Dynamic changes in the distribution of cytoplasmic myosin during Drosophila embryogenesis. Development. 1991 Jan;111(1):1–14. [PubMed]
  • Zot HG, Doberstein SK, Pollard TD. Myosin-I moves actin filaments on a phospholipid substrate: implications for membrane targeting. J Cell Biol. 1992 Jan;116(2):367–376. [PMC free article] [PubMed]

Articles from The Journal of Cell Biology are provided here courtesy of The Rockefeller University Press


Save items

Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...


  • Compound
    PubChem chemical compound records that cite the current articles. These references are taken from those provided on submitted PubChem chemical substance records. Multiple substance records may contribute to the PubChem compound record.
  • Gene
    Gene records that cite the current articles. Citations in Gene are added manually by NCBI or imported from outside public resources.
  • GEO Profiles
    GEO Profiles
    Gene Expression Omnibus (GEO) Profiles of molecular abundance data. The current articles are references on the Gene record associated with the GEO profile.
  • HomoloGene
    HomoloGene clusters of homologous genes and sequences that cite the current articles. These are references on the Gene and sequence records in the HomoloGene entry.
  • Pathways + GO
    Pathways + GO
    Pathways and biological systems (BioSystems) that cite the current articles. Citations are from the BioSystems source databases (KEGG and BioCyc).
  • PubMed
    PubMed citations for these articles
  • Substance
    PubChem chemical substance records that cite the current articles. These references are taken from those provided on submitted PubChem chemical substance records.
  • Taxonomy
    Taxonomy records associated with the current articles through taxonomic information on related molecular database records (Nucleotide, Protein, Gene, SNP, Structure).
  • Taxonomy Tree
    Taxonomy Tree

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...