Optimization of tamoxifen-induced gene regulation in cardiovascular research

The Cre-loxP system is a powerful and versatile tool to control site-specific recombination of mammalian genomic DNA. Site-specific Cre recombinase-mediated DNA recombination allows for the conditional control of gene expression within transgenic animals in a tissuespecific manner by employing a promoter known to be expressed specifically in such tissue of interest. More specifically, the gene of interest is flanked (floxed) by two loxP (locus of x-over, P1) sites in the presence of Cre recombinase, which then catalyzes the site-specific recombination of DNA between those loxP sites, leading to tissue-specific gene editing. However, the approach is flawed by the lack of control over the timing of Cre recombinase expression which often parallels the expression of the chosen promoter. Consequently, Cre-