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Mechanism of brush border contractility studied by the quick-freeze, deep-etch method

We have analyzed terminal web contraction in sheets of glycerinated chicken small intestine epithelium and in isolated intestinal brush borders using a quick-freeze, deep-etch, rotary shadow replication technique. In the presence of Mg-ATP at 37 degrees C, the terminal web region of each cell in the...

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Detalles Bibliográficos
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1983
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2112654/
https://www.ncbi.nlm.nih.gov/pubmed/6601660
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description We have analyzed terminal web contraction in sheets of glycerinated chicken small intestine epithelium and in isolated intestinal brush borders using a quick-freeze, deep-etch, rotary shadow replication technique. In the presence of Mg-ATP at 37 degrees C, the terminal web region of each cell in the glycerinated sheet and of each isolated brush border became severely constricted at the level of its zonula adherens (ZA). Consequently, the individual brush borders rounded up, splaying out their microvilli in fanlike patterns. The most prominent ultrastructural changes that occurred during terminal web contraction were a dramatic decrease in the diameter of the circumferential ring composed of a bundle of 8-9-nm filaments adjacent to the zonula adherens and a decrease in the number of cross-linkers between the microvillus rootlets. Microvilli were not retracted into the terminal web. We have used myosin S1 decoration to demonstrate that most of the circumferential bundle filaments are actin and that the actin filaments are arranged in the bundle with mixed polarity. Some filaments within the bundle did not decorate with myosin S1 and had tiny projections that appeared to be attached to adjacent actin filaments. Because of their morphology and immunofluorescent localization of myosin within this region of the terminal web, we propose that these undecorated filaments are myosin. From these results, we conclude that brush border contraction is caused primarily by an active sliding of actin and myosin filaments within the circumferential bundle of filaments associated with the ZA.
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spelling pubmed-21126542008-05-01 Mechanism of brush border contractility studied by the quick-freeze, deep-etch method J Cell Biol Articles We have analyzed terminal web contraction in sheets of glycerinated chicken small intestine epithelium and in isolated intestinal brush borders using a quick-freeze, deep-etch, rotary shadow replication technique. In the presence of Mg-ATP at 37 degrees C, the terminal web region of each cell in the glycerinated sheet and of each isolated brush border became severely constricted at the level of its zonula adherens (ZA). Consequently, the individual brush borders rounded up, splaying out their microvilli in fanlike patterns. The most prominent ultrastructural changes that occurred during terminal web contraction were a dramatic decrease in the diameter of the circumferential ring composed of a bundle of 8-9-nm filaments adjacent to the zonula adherens and a decrease in the number of cross-linkers between the microvillus rootlets. Microvilli were not retracted into the terminal web. We have used myosin S1 decoration to demonstrate that most of the circumferential bundle filaments are actin and that the actin filaments are arranged in the bundle with mixed polarity. Some filaments within the bundle did not decorate with myosin S1 and had tiny projections that appeared to be attached to adjacent actin filaments. Because of their morphology and immunofluorescent localization of myosin within this region of the terminal web, we propose that these undecorated filaments are myosin. From these results, we conclude that brush border contraction is caused primarily by an active sliding of actin and myosin filaments within the circumferential bundle of filaments associated with the ZA. The Rockefeller University Press 1983-05-01 /pmc/articles/PMC2112654/ /pubmed/6601660 Text en This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Articles
Mechanism of brush border contractility studied by the quick-freeze, deep-etch method
title Mechanism of brush border contractility studied by the quick-freeze, deep-etch method
title_full Mechanism of brush border contractility studied by the quick-freeze, deep-etch method
title_fullStr Mechanism of brush border contractility studied by the quick-freeze, deep-etch method
title_full_unstemmed Mechanism of brush border contractility studied by the quick-freeze, deep-etch method
title_short Mechanism of brush border contractility studied by the quick-freeze, deep-etch method
title_sort mechanism of brush border contractility studied by the quick-freeze, deep-etch method
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2112654/
https://www.ncbi.nlm.nih.gov/pubmed/6601660