Summary
The detergent-resistant cytoskeleton ofPhysarum polycephalum myxamoebae was isolated by extraction of cells in buffers containing Triton X-100. The cytoskeleton of myxamoebae was seen to be composed of a network of 6 nm microfilaments and microtubules when examined in the electron microscope as negatively stained whole mount preparations, or in thin sections. Cytoplasmic microtubules originated from a microtubule organising centre which remained in close association both with the nucleus and centrioles in detergent-lysed preparations. Nuclear pore complexes remained attached to the nuclear surface despite the removal of nuclear membranes during Triton extraction.
Preparations were examined using SDS-polyacrylamide gel electrophoresis and two-dimensional polyacrylamide gel electrophoresis. Actin and tubulin were major components of the Triton-resistant structure. Two dimensional polyacrylamide gel electrophoresis indicated the presence of tubulin and actin species in the myxamoebal cytoskeleton. Other prominent protein components had apparent relative molecular masses of approx. 27 K and 220 K. Lysis of cells in buffers containing Ca2+ resulted in the removal of microtubules from the cytoskeleton and a specific decrease in the amount of tubulin in gels of Ca2+-treated material; some tubulin spots did however remain, possibly representing centriolar tubulins.
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Clayton, L., Pogson, C.I. & Gull, K. Ultrastructural and biochemical characterisation of the cytoskeleton ofPhysarum polycephalum myxamoebae. Protoplasma 118, 181–191 (1983). https://doi.org/10.1007/BF01281801
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DOI: https://doi.org/10.1007/BF01281801