Col1a1^{tm6(EF1-luc2)Nki}

FVB.129P2-Cdkn2a Nf2 Trp53Col1a1 ES cells were retargeted to replace the frt-flanked PGK-Neo cassette in the 3' UTR of the Col1a1 by a "Flp-in" plasmid encoding a frt-lox66-EF1-lox71-Luc2 inversion transgene, called inv-Cag-Luc2, by co-transfected with a Flpe-expressing plasmid to facilitate recombination into the 3' UTR of the Col1a1 locus. This transgene contains the constitutive EF1alpha promoter that drives the expression of the Hygromycin-resistance gene, present in the targeted Col1a1 locus. Upon expression of the Cre recombinase, the promoter is inverted due to flanking mutant loxP sites, i.e. lox66 and lox71, placing the promoter in front of the firefly Luciferase2 gene. (J:188992, J:210103)