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Actin-dependent cell elongation in teleost retinal rods: requirement for actin filament assembly
Teleost retinal rods elongate when exposed to light. Elongation is mediated by a narrow necklike region called the myoid. In the cichlid Sarotherodon mossambicus, the rod inner segment (composed of the myoid with adjacent ellipsoid) increases in length from 12 micrometers in the dark to 41 micromete...
Formato: | Texto |
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Lenguaje: | English |
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The Rockefeller University Press
1981
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2111817/ https://www.ncbi.nlm.nih.gov/pubmed/6894759 |
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collection | PubMed |
description | Teleost retinal rods elongate when exposed to light. Elongation is mediated by a narrow necklike region called the myoid. In the cichlid Sarotherodon mossambicus, the rod inner segment (composed of the myoid with adjacent ellipsoid) increases in length from 12 micrometers in the dark to 41 micrometers in the light. Long light-adapted myoids contain longitudinally oriented microtubules and bundles of parallel 60-A filaments that we have identified as actin by their ability to bind myosin subfragment 1. In short dark-adapted myoids, only microtubules are recognizable. Colchicine experiments reveal that light-induced rod elongation can occur in the absence of myoid microtubules. Intraocular injections of colchicine at concentrations that disrupt virtually all rod myoid microtubules do not block rod elongation. However, rod elongation is blocked by intraocular injections of cytochalasin B or cytochalasin D. The hierarchy of effectiveness of these drugs is consistent with their effectiveness in inhibiting actin assembly and in disrupting other actin-dependent motile processes. On the basis of ultrastructural observations and the results of these inhibitor studies, we propose that the forces responsible for rod elongation are dependent not on microtubules but on actin filament assembly. |
format | Text |
id | pubmed-2111817 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 1981 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-21118172008-05-01 Actin-dependent cell elongation in teleost retinal rods: requirement for actin filament assembly J Cell Biol Articles Teleost retinal rods elongate when exposed to light. Elongation is mediated by a narrow necklike region called the myoid. In the cichlid Sarotherodon mossambicus, the rod inner segment (composed of the myoid with adjacent ellipsoid) increases in length from 12 micrometers in the dark to 41 micrometers in the light. Long light-adapted myoids contain longitudinally oriented microtubules and bundles of parallel 60-A filaments that we have identified as actin by their ability to bind myosin subfragment 1. In short dark-adapted myoids, only microtubules are recognizable. Colchicine experiments reveal that light-induced rod elongation can occur in the absence of myoid microtubules. Intraocular injections of colchicine at concentrations that disrupt virtually all rod myoid microtubules do not block rod elongation. However, rod elongation is blocked by intraocular injections of cytochalasin B or cytochalasin D. The hierarchy of effectiveness of these drugs is consistent with their effectiveness in inhibiting actin assembly and in disrupting other actin-dependent motile processes. On the basis of ultrastructural observations and the results of these inhibitor studies, we propose that the forces responsible for rod elongation are dependent not on microtubules but on actin filament assembly. The Rockefeller University Press 1981-06-01 /pmc/articles/PMC2111817/ /pubmed/6894759 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 Actin-dependent cell elongation in teleost retinal rods: requirement for actin filament assembly |
title | Actin-dependent cell elongation in teleost retinal rods: requirement for actin filament assembly |
title_full | Actin-dependent cell elongation in teleost retinal rods: requirement for actin filament assembly |
title_fullStr | Actin-dependent cell elongation in teleost retinal rods: requirement for actin filament assembly |
title_full_unstemmed | Actin-dependent cell elongation in teleost retinal rods: requirement for actin filament assembly |
title_short | Actin-dependent cell elongation in teleost retinal rods: requirement for actin filament assembly |
title_sort | actin-dependent cell elongation in teleost retinal rods: requirement for actin filament assembly |
topic | Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2111817/ https://www.ncbi.nlm.nih.gov/pubmed/6894759 |