DNA excision in liver by an albumin-Cre transgene occurs progressively with age

We have previously described a line of albumin-Cre (Alb-Cre) transgenic mice C57BL6-TgN(AlbCre)21Mgn in which the promoter and upstream enhancer of the rat albumin gene (Fig. When used in combination with a loxed glucokinase gene allele (gk lox ), the Alb-Cre trangene led to a liver-specific knockout of this enzyme Southern blot analysis of DNAs isolated from 8-week-old gk lox/lox Alb-Cre mice showed more than 80% conversion of the gk lox allele to a deleted allele (gk del ) in liver with no recombination in other tissues At this age, Western blot analysis and immunocytochemistry of liver samples showed no detectable glucokinase expression, suggesting that recombination in hepatocytes was essentially complete.