STUDIES OF THE NUCLEAR MATRIX AND CYTOSKELETON OF XENOPUS LAEVIS ERYTHROCYTES AND SPERMATOGENIC CELLS.
Item
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Title
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STUDIES OF THE NUCLEAR MATRIX AND CYTOSKELETON OF XENOPUS LAEVIS ERYTHROCYTES AND SPERMATOGENIC CELLS.
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Identifier
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AAI8401932
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identifier
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8401932
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Creator
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GAMBINO, JOHN.
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Contributor
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Ronald A. Eckhardt
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Date
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1983
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biology, General
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Abstract
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Nuclear and cytoskeletal structures were examined in a variety of Xenopus cell types. Spermatogenic cells were used to study nuclear matrix changes during meiotic prophase. From this study, it was demonstrated that in contrast to previous reports, nuclear matrices with NPLCs and SCs could be isolated from spermatocytes provided gentle isolation procedures were utilized. It was also shown that the NPLC becomes fragmented during chromosome synapsis.;Erythrocyte nuclear matrices were demonstrated to lack intranuclear matrix elements and consist solely of the nuclear lamina. The lamina was isolated in association with cytoskeletal elements (cyto-nuclear skeletons) such as centrioles and intermediate filaments. The later extends to the outer subsurface cytoskeletal shell. In erythrocyte cyto-nuclear skeletons, the nuclear lamina was often observed to have the overall shape and position of intact nuclei. Electron microscopic and electrophoretic characterization of these high salt treated structures suggests that although microtubules were no longer ultrastructurally observable, tubulin remained associated with the cyto-nuclear skeletons. This association may reflect unique interactions between this protein and other cytoskeletal components as opposed to simply non-specific binding.;Xenopus erythrocyte marginal band microtubules were not depolymerized in intact cells or cytoskeletons by agents (cold, microtubule poisons, the direct action of calcium) which solubilize cytoplasmic microtubules. They were disassembled by calcium lysis. Calcium lysis appears to influence specifically tubulin and another high molecular weight cytoskeletal polypeptide since electrophoretic profiles of calcium lysed erythrocytes do not differ in other ways from those of cells lysed in the presence of EGTA. Moreover, the calcium released tubulin was not degraded. Therefore, it appears that calcium activates cytoplasmic factors, possibly mediated by calmodulin, which result in a sudden change in marginal band stability properties.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
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Program
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Biology
