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Calcium buffer injections delay cleavage in Xenopus laevis blastomeres
Microinjection of calcium buffers into the two-cell Xenopus laevis embryo delays cell division in a dose-dependent manner. Four calcium buffers in the BAPTA series with different affinities for calcium were used to distinguish between a localized calcium gradient regulating cleavage and the global c...
Formato: | Texto |
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Lenguaje: | English |
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The Rockefeller University Press
1993
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2119655/ https://www.ncbi.nlm.nih.gov/pubmed/8320261 |
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collection | PubMed |
description | Microinjection of calcium buffers into the two-cell Xenopus laevis embryo delays cell division in a dose-dependent manner. Four calcium buffers in the BAPTA series with different affinities for calcium were used to distinguish between a localized calcium gradient regulating cleavage and the global calcium concentration regulating this event. DibromoBAPTA (Kd = 1.5 microM) was found to delay cleavage at the lowest intracellular concentration (1.3 mM) of the four buffers tested. The effectiveness of the calcium buffers was dependent upon the buffer dissociation constant but not in a linear fashion. The concentration of buffer required to delay cleavage increased as the buffer's dissociation constant shifted above or below that of the optimum buffer, dibromoBAPTA. This relationship between a calcium buffer's effectiveness at delaying cleavage and its calcium affinity provides support for the hypothesis that a calcium concentration gradient is required for normal cell cycle progression (Speksnijder, J. E., A. L. Miller, M. H. Weisenseel, T.-H. Chen, and L. F. Jaffe. 1989. Proc. Natl. Acad. Sci. USA. 86:6607-6611). DibromoBAPTA was also injected with two different amounts of coinjected calcium to test the possibility that the free calcium concentration of the buffer solution is the important parameter for delaying cleavage. However, we found that changes in buffer concentration have a much stronger effect than changes in the free calcium concentration. This observation supports the hypothesis that BAPTA-type buffers exert their effect by shuttling calcium from regions of high concentration to those of lower concentration, reducing any calcium concentration gradients present in the Xenopus embryo. |
format | Text |
id | pubmed-2119655 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 1993 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-21196552008-05-01 Calcium buffer injections delay cleavage in Xenopus laevis blastomeres J Cell Biol Articles Microinjection of calcium buffers into the two-cell Xenopus laevis embryo delays cell division in a dose-dependent manner. Four calcium buffers in the BAPTA series with different affinities for calcium were used to distinguish between a localized calcium gradient regulating cleavage and the global calcium concentration regulating this event. DibromoBAPTA (Kd = 1.5 microM) was found to delay cleavage at the lowest intracellular concentration (1.3 mM) of the four buffers tested. The effectiveness of the calcium buffers was dependent upon the buffer dissociation constant but not in a linear fashion. The concentration of buffer required to delay cleavage increased as the buffer's dissociation constant shifted above or below that of the optimum buffer, dibromoBAPTA. This relationship between a calcium buffer's effectiveness at delaying cleavage and its calcium affinity provides support for the hypothesis that a calcium concentration gradient is required for normal cell cycle progression (Speksnijder, J. E., A. L. Miller, M. H. Weisenseel, T.-H. Chen, and L. F. Jaffe. 1989. Proc. Natl. Acad. Sci. USA. 86:6607-6611). DibromoBAPTA was also injected with two different amounts of coinjected calcium to test the possibility that the free calcium concentration of the buffer solution is the important parameter for delaying cleavage. However, we found that changes in buffer concentration have a much stronger effect than changes in the free calcium concentration. This observation supports the hypothesis that BAPTA-type buffers exert their effect by shuttling calcium from regions of high concentration to those of lower concentration, reducing any calcium concentration gradients present in the Xenopus embryo. The Rockefeller University Press 1993-07-02 /pmc/articles/PMC2119655/ /pubmed/8320261 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 Calcium buffer injections delay cleavage in Xenopus laevis blastomeres |
title | Calcium buffer injections delay cleavage in Xenopus laevis blastomeres |
title_full | Calcium buffer injections delay cleavage in Xenopus laevis blastomeres |
title_fullStr | Calcium buffer injections delay cleavage in Xenopus laevis blastomeres |
title_full_unstemmed | Calcium buffer injections delay cleavage in Xenopus laevis blastomeres |
title_short | Calcium buffer injections delay cleavage in Xenopus laevis blastomeres |
title_sort | calcium buffer injections delay cleavage in xenopus laevis blastomeres |
topic | Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2119655/ https://www.ncbi.nlm.nih.gov/pubmed/8320261 |