Prolonged Cre expression driven by the α-myosin heavy chain promoter can be cardiotoxic
| Autor: | Leslie A. Leinwand, Joseph Azofeifa, Robin D. Dowell, Emily K. Pugach, Phillip A. Richmond |
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| Rok vydání: | 2015 |
| Předmět: |
Genetically modified mouse
Cell type Genotype DNA damage Cre recombinase 030204 cardiovascular system & hematology Biology Article 03 medical and health sciences Mice 0302 clinical medicine Conditional gene knockout Myosin Animals Humans Myocytes Cardiac Promoter Regions Genetic Molecular Biology Gene 030304 developmental biology Mice Knockout 0303 health sciences Integrases Myosin Heavy Chains Molecular biology Cardiotoxicity 3. Good health MYH6 Cardiology and Cardiovascular Medicine DNA Damage |
| Zdroj: | Journal of molecular and cellular cardiology. 86 |
| ISSN: | 1095-8584 |
| Popis: | Studying the importance of genetic factors in a desired cell type or tissue necessitates the use of precise genetic tools. With the introduction of bacteriophage Cre recombinase/loxP mediated DNA editing and promoter-specific Cre expression, it is feasible to generate conditional knockout mice in which particular genes are disrupted in a cell type-specific manner in vivo. In cardiac myocytes, this is often achieved through α-myosin heavy chain promoter (αMyHC)-driven Cre expression in conjunction with a loxP-site flanked gene of interest. Recent studies in other cell types demonstrate toxicity of Cre expression through induction of DNA damage. However, it is unclear to what extent the traditionally used αMyHC-Cre line [1] may exhibit cardiotoxicity. Further, the genotype of αMyHC-Cre(+/-) is not often included as a control group in cardiac myocyte-specific knockout studies. Here we present evidence that these αMyHC-Cre(+/-) mice show molecular signs of cardiac toxicity by 3months of age and exhibit decreased cardiac function by 6months of age compared to wild-type littermates. Hearts from αMyHC-Cre(+/-) mice also display evidence of fibrosis, inflammation, and DNA damage. Interestingly, some of the early functional changes observed in αMyHC-Cre(+/-) mice are sexually dimorphic. Given the high level of Cre recombinase expression resulting from expression from the αMyHC promoter, we asked if degenerate loxP-like sites naturally exist in the mouse genome and if so, whether they are affected by Cre in the absence of canonical loxP-sites. Using a novel bioinformatics search tool, we identified 619 loxP-like sites with 4 or less mismatches to the canonical loxP-site. 227 sites overlapped with annotated genes and 55 of these genes were expressed in cardiac muscle. Expression of ~26% of the 27 genes tested was disrupted in αMyHC-Cre(+/-) mice indicating potential targeting by Cre. Taken together, these results highlight both the importance of using αMyHC-Cre mice as controls in conditional knockout studies as well as the need for a less cardiotoxic Cre driver for the field. |
| Databáze: | OpenAIRE |
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