Actin-like filaments in the cleavage furrow of newt egg*

Perry, Margaret M.; John, Huw A.; Thomas, N

doi:10.1016/s0014-4827(71)80075-7

Cited by 150 publications

(57 citation statements)

References 15 publications

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“…In many tissues 4 nm filaments are associated with the cell surface and ~o n m filaments with deeper seated sites, but subsurface filaments ranging from 4 to 10 nm have also been reported (Perry, John & Thomas, 1971 ;Tucker, 1971), while here approximately 10 nm filaments are common to both regions. Identification of filaments is easiest where they form extensive parallel arrays associated with large-scale 54 P. T. P. O L I V E R movements.…”

Section: Discussionmentioning

confidence: 57%

Conidiophore and Spore Development in Aspergillus nidulans

Oliver

1972

Journal of General Microbiology

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S U M M A R YConidiophore development was studied in wild-type and structurally defective mutants of Aspergillus nidulans. Cytoplasmic vesicles were found concentrated at growing apices. Plasmalemmasomes occurred frequently in the subapical and basal cytoplasm of growing sterigmata and near their developing septa ; after septum formation they were flattened against the septa and the wall of the older cell and were associated with lomasomes. At this stage the wall developed a superficial lamina; the basipetally budding spore chain was invested from its initiation by a continuation of this lamina. The lamina was also associated with a dense network in the medium around the basal mycelium. The inner, secondary wall of the conidiophore became more electron-lucent with age; the continuity between this wall and the single wall of the sterigmata suggested this structure to be the site of action of the bristle locus. Pigmentation of wild-type and mutant conidiophores was associated with an electron-dense modification of the outer, primary wall. Stratification of the spore wall was indicated only by the similar development of a layer of electron-dense material. Cytoplasmic microfilaments were observed in all parts of the colony.

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Section: Discussionmentioning

confidence: 57%

Conidiophore and Spore Development in Aspergillus nidulans

Oliver

1972

Journal of General Microbiology

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“…These preparative methods gave no information concerning the localization of the actin within the egg, but there is good evidence lor its presence in the cleavage furrow during cytokinesis, where it was seen first in the electron microscope as bundles of microfilaments (28,30,37). Actin has been localized in the cleavage furrow in a variety of other cell types ( 1,21,27,29,34) and this actin has been specifically labeled with heavy meromyosin (31). The investigations reported here were begun with the aim of determining whether the methods developed for the polymerization of tubulin to microtubules in mammalian brain (2, 39) could be used to prepare tubulin from the sea urchin egg.…”

Section: Introductionmentioning

confidence: 99%

Preparation and purification of polymerized actin from sea urchin egg extracts.

Kane¹

1975

The Journal of Cell Biology

219

145

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Isotonic extracts of the soluble cytoplasmic proteins of sea urchin eggs, containing sufficient EGTA to reduce the calcium concentration to low levels, form a dense gel on warming to 35 40~ Although this procedure is similar to that used to polymerize tubulin from mammalian brain, sodium dodecyl sulfate-polyacrylamide gel electrophoresis shows this gel to have actin as a major component and to contain no tubulin. If such extracts are dialyzed against dilute salt solution, they no longer respond to warming, but gelation will occur if they are supplemented with 1 mM ATP and 0.020 M KC1 before heating. Gelation is not temperature reversible, but the gelled material can be dissolved in 0.6-1 M J~C1 and these solutions contain F-actin filaments. These filaments slowly aggregate to microscopic, birefringent fibrils when l mM ATP is added to the solution, and this procedure provides a simple method for preparing purified actin. The supernate remaining after actin removal contains the other two components of the gel, proteins of approximately 58,000 and 220,000 mol wt. These two proteins plus actin recombine to form the original gel material when the ionic strength is reduced. This reaction is reversible at 0~ and no heating is required.Following the demonstration of an actin-like protein, similar in properties to muscle actin, in myxomycete plasmodium (9, 10), similar methods revealed the presence of a cytoplasmic actin in unfertilized sea urchin eggs. This sea urchin egg actin was first identified and separated through its combination with rabbit muscle myosin (8,18,19), and the protein was later prepared directly from egg extracts by salting out with ammonium sulfate (17). These preparative methods gave no information concerning the localization of the actin within the egg, but there is good evidence lor its presence in the cleavage furrow during cytokinesis, where it was seen first in the electron microscope as bundles of microfilaments (28,30,37). Actin has been localized in the cleavage furrow in a variety of other cell types ( 1,21,27,29,34) and this actin has been specifically labeled with heavy meromyosin (31). The investigations reported here were begun with the aim of determining whether the methods developed for the polymerization of tubulin to microtubules in mammalian brain (2, 39) could be used to prepare tubulin from the sea urchin egg. Marine eggs are an excellent source of isolated mitotic apparatuses for the investigation of the role of microtubules in chromosome movement, but up to this time only the interaction of mammalian brain tuhulin with such isolated mitotic apparatuses has been reported (12, 25). Our attempts to prepare tubulin from extracts of sea urchin eggs with the methods developed for mammalian material were unsuccessful, and a number of modifications of this method were made to adapt it to the

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“…These cytoplasmic elements, reported to be 40-80 A in diameter, are found in a wide variety of cells-from the motile amoebae (1-6) to the endothelial absorptive cells of the intestine, where they form the core of the microvilli (7) . The presence of microfilaments has been correlated with numerous functions : inter-and intracellular movements (2,5,8), cytokinesis (9)(10)(11)(12), the establishment and maintenance of form Recently, Yang and Perdue isolated an actin-like protein from cultured chick embryo fibroblasts (35) . This protein was electrophoretically homogeneous in two acrylamide-gel systems-sodium dodecyl sulfate and urea .…”

Section: Introductionmentioning

confidence: 99%

The Distribution, Ultrastructure, and Chemistry of Microfilaments in Cultured Chick Embryo Fibroblasts

Perdue

1973

The Journal of Cell Biology

132

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The distribution, ultrastructure, and chemistry of microfilaments in cultured chick embryo fibroblasts were studied by thin sectioning of flat-embedded untreated and glycerol-extracted cells, histochemical and immunological electron microscopic procedures, and the negative staining of cells cultured on electron microscopic grids . In these cultured cells, the microfilaments are arranged into thick bundles that are disposed longitudinally and in looser arrangements in the fusiform-shaped cells . In the latter case, they are concentrated along the margins of the flattened cell, on the dorsal surface, and particularly at the ends of the cell and its ventral surface, where contact is made with the plastic dish or with other cells . Extracellular filaments, presumably originating from within the cell, are found at these points of contact . The microfilaments are composed in part of an actin-like protein .These filaments are between 70 and 90 A in diameter, they are stable in 50 0]0 glycerol, they have an endogenous ATPase (myosin-like?) associated with them, they bind rabbit muscle heavy meromyosin, and they specifically bind antibody directed against isolated actin-like protein . In the cultured chick embryo fibroblasts, the microfilaments are essential for the establishment and maintenance of form, and they are probably critical elements for adhesion and motility . The microfilaments might also serve as stabilizers of intramembranous particle fluidity .

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Actin-like filaments in the cleavage furrow of newt egg*

Cited by 150 publications

References 15 publications

Conidiophore and Spore Development in Aspergillus nidulans

Conidiophore and Spore Development in Aspergillus nidulans

Preparation and purification of polymerized actin from sea urchin egg extracts.

The Distribution, Ultrastructure, and Chemistry of Microfilaments in Cultured Chick Embryo Fibroblasts

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