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Hemizygous Le-Cre Transgenic Mice Have Severe Eye Abnormalities on Some Genetic Backgrounds in the Absence of LoxP Sites
Eye phenotypes were investigated in Le-Cre(Tg/−); Pax6(fl/+) mice, which were expected to show tissue-specific reduction of Pax6 in surface ectoderm derivatives. To provide a better comparison with our previous studies of Pax6(+/−) eye phenotypes, hemizygous Le-Cre(Tg/−) and heterozygous Pax6(fl/+)m...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2014
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4182886/ https://www.ncbi.nlm.nih.gov/pubmed/25272013 http://dx.doi.org/10.1371/journal.pone.0109193 |
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author | Dorà, Natalie J. Collinson, J. Martin Hill, Robert E. West, John D. |
author_facet | Dorà, Natalie J. Collinson, J. Martin Hill, Robert E. West, John D. |
author_sort | Dorà, Natalie J. |
collection | PubMed |
description | Eye phenotypes were investigated in Le-Cre(Tg/−); Pax6(fl/+) mice, which were expected to show tissue-specific reduction of Pax6 in surface ectoderm derivatives. To provide a better comparison with our previous studies of Pax6(+/−) eye phenotypes, hemizygous Le-Cre(Tg/−) and heterozygous Pax6(fl/+)mice were crossed onto the CBA/Ca genetic background. After the Le-Cre transgene had been backcrossed to CBA/Ca for seven generations, significant eye abnormalities occurred in some hemizygous Le-Cre(Tg/−); Pax6(+/+) controls (without a floxed Pax6(fl) allele) as well as experimental Le-Cre(Tg/−); Pax6(fl/+) mice. However, no abnormalities were seen in Le-Cre(−/−); Pax6(fl/+) or Le-Cre(−/−); Pax6(+/+) controls (without the Le-Cre transgene). The severity and frequency of the eye abnormalities in Le-Cre(Tg/−); Pax6(+/+) control mice diminished after backcrossing Le-Cre(Tg/−) mice to the original FVB/N strain for two generations, showing that the effect was reversible. This genetic background effect suggests that the eye abnormalities are a consequence of an interaction between the Le-Cre transgene and alleles of unknown modifier genes present in certain genetic backgrounds. The abnormalities were also ameliorated by introducing additional Pax6 gene copies on a CBA/Ca background, suggesting involvement of Pax6 depletion in Le-Cre(Tg/−); Pax6(+/+) mice rather than direct action of Cre recombinase on cryptic pseudo-loxP sites. One possibility is that expression of Cre recombinase from the Pax6-Le regulatory sequences in the Le-Cre transgene depletes cofactors required for endogenous Pax6 gene expression. Our observation that eye abnormalities can occur in hemizygous Le-Cre(Tg/−); Pax6(+/+) mice, in the absence of a floxed allele, demonstrates the importance of including all the relevant genetic controls in Cre-loxP experiments. |
format | Online Article Text |
id | pubmed-4182886 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2014 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-41828862014-10-07 Hemizygous Le-Cre Transgenic Mice Have Severe Eye Abnormalities on Some Genetic Backgrounds in the Absence of LoxP Sites Dorà, Natalie J. Collinson, J. Martin Hill, Robert E. West, John D. PLoS One Research Article Eye phenotypes were investigated in Le-Cre(Tg/−); Pax6(fl/+) mice, which were expected to show tissue-specific reduction of Pax6 in surface ectoderm derivatives. To provide a better comparison with our previous studies of Pax6(+/−) eye phenotypes, hemizygous Le-Cre(Tg/−) and heterozygous Pax6(fl/+)mice were crossed onto the CBA/Ca genetic background. After the Le-Cre transgene had been backcrossed to CBA/Ca for seven generations, significant eye abnormalities occurred in some hemizygous Le-Cre(Tg/−); Pax6(+/+) controls (without a floxed Pax6(fl) allele) as well as experimental Le-Cre(Tg/−); Pax6(fl/+) mice. However, no abnormalities were seen in Le-Cre(−/−); Pax6(fl/+) or Le-Cre(−/−); Pax6(+/+) controls (without the Le-Cre transgene). The severity and frequency of the eye abnormalities in Le-Cre(Tg/−); Pax6(+/+) control mice diminished after backcrossing Le-Cre(Tg/−) mice to the original FVB/N strain for two generations, showing that the effect was reversible. This genetic background effect suggests that the eye abnormalities are a consequence of an interaction between the Le-Cre transgene and alleles of unknown modifier genes present in certain genetic backgrounds. The abnormalities were also ameliorated by introducing additional Pax6 gene copies on a CBA/Ca background, suggesting involvement of Pax6 depletion in Le-Cre(Tg/−); Pax6(+/+) mice rather than direct action of Cre recombinase on cryptic pseudo-loxP sites. One possibility is that expression of Cre recombinase from the Pax6-Le regulatory sequences in the Le-Cre transgene depletes cofactors required for endogenous Pax6 gene expression. Our observation that eye abnormalities can occur in hemizygous Le-Cre(Tg/−); Pax6(+/+) mice, in the absence of a floxed allele, demonstrates the importance of including all the relevant genetic controls in Cre-loxP experiments. Public Library of Science 2014-10-01 /pmc/articles/PMC4182886/ /pubmed/25272013 http://dx.doi.org/10.1371/journal.pone.0109193 Text en © 2014 Dorà et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited. |
spellingShingle | Research Article Dorà, Natalie J. Collinson, J. Martin Hill, Robert E. West, John D. Hemizygous Le-Cre Transgenic Mice Have Severe Eye Abnormalities on Some Genetic Backgrounds in the Absence of LoxP Sites |
title | Hemizygous Le-Cre Transgenic Mice Have Severe Eye Abnormalities on Some Genetic Backgrounds in the Absence of LoxP Sites |
title_full | Hemizygous Le-Cre Transgenic Mice Have Severe Eye Abnormalities on Some Genetic Backgrounds in the Absence of LoxP Sites |
title_fullStr | Hemizygous Le-Cre Transgenic Mice Have Severe Eye Abnormalities on Some Genetic Backgrounds in the Absence of LoxP Sites |
title_full_unstemmed | Hemizygous Le-Cre Transgenic Mice Have Severe Eye Abnormalities on Some Genetic Backgrounds in the Absence of LoxP Sites |
title_short | Hemizygous Le-Cre Transgenic Mice Have Severe Eye Abnormalities on Some Genetic Backgrounds in the Absence of LoxP Sites |
title_sort | hemizygous le-cre transgenic mice have severe eye abnormalities on some genetic backgrounds in the absence of loxp sites |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4182886/ https://www.ncbi.nlm.nih.gov/pubmed/25272013 http://dx.doi.org/10.1371/journal.pone.0109193 |
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