| First Author | Turlo KA | Year | 2010 |
| Journal | Genetics | Volume | 186 |
| Issue | 3 | Pages | 959-67 |
| PubMed ID | 20813881 | Mgi Jnum | J:165707 |
| Mgi Id | MGI:4838337 | Doi | 10.1534/genetics.110.121608 |
| Citation | Turlo KA, et al. (2010) When cre-mediated recombination in mice does not result in protein loss. Genetics 186(3):959-67 |
| abstractText | Cre/loxP recombination enables cellular specificity and, in the case of inducible systems, temporal control of genomic deletions. Here we used a SM22alpha tamoxifen-inducible Cre line to inactivate beta1 integrin in adult smooth muscle. Interestingly, analysis of two distinct beta1 loxP transgenic mice revealed vastly different outcomes after beta1 integrin deletion. Lethality occurred 4 weeks postinduction in one Cre/loxP line, while no apparent phenotype was seen in the other line. Genetic analysis revealed appropriate DNA excision in both cases; however, differences were found in the degree of protein loss with absolutely no change in protein levels in the model that lacked a phenotype. Seeking to understand protein persistence despite appropriate recombination, we first validated the flox allele using a constitutive Cre line and demonstrated its ability to mediate effective protein inactivation. We then examined the possibility of heterozygous cell selection, protein turnover, and deletion efficiency with no success for explaining the phenotype. Finally, we documented the presence of the Cre-recombination episomal product, which persisted in tissue samples with no protein loss. The product was only noted in cells with low proliferative capacity. These findings highlight the potential for protein expression from the products of Cre-recombinase excised genes, particularly when deletion occurs in low turnover populations. |
