Ready-to-use models

Cre recombinase is driven by the Albumin promoter:

• Hepatocyte-specific expression
• 90% of Cre-mediated excision achieved in hepatocytes at 6 and 12-weeks-old
• No Cre expression in other tissues: brain, heart, spleen, kidney or skeletal muscle

Line characterization:

• An albumin-Cre mouse was mated with a Rosa 26 reporter mouse (loxP-STOP-loxP-lacZ). Upon Cre gene expression, the recombinase activity results in the excision of the STOP sequence and the expression of the reporter gene. The β-galactosidase staining reflects Cre recombinase activity in vivo and shows evidence of cytoplasmic β-galactosidase activity in most hepatocytes (See figure B).
• Cre-mediated recombination was further analyzed using a glucokinase conditional knock-out mouse model (gk^lox/lox) mated with the albumin-Cre mouse line. A 90% knock-out of this enzyme was observed in the liver, whereas no excision was detected in other tissues tested (see Figure A). Moreover, the efficiency of excision is age-dependent as 90% of Cre-mediated excision is achieved at 6 and 12-weeks-old. (see figure C)

Liver specific expression of the recombinase Cre in the albumin-Cre mouse line Figure A - Amplification by reverse transcriptase-PCR of hGH-Cre mRNA in liver (Liv) of Alb-cre mouse. Spl, spleen; Kid, kidney; Hrt, heart; SkM, skeletal muscle; Brn, brain. Figure B - LacZ-stained liver from lacZ/Alb-cre mice showing cytoplasmic β-galactosidase activity in most hepatocytes. lacZ staining was specific to the liver in this line of mice. Figure C - Southern blot analysis of liver DNA from 1-day-old, 1-, 3-, 6- and 12-week old gklox/lox/Albumine-Cre mice. The excision seems to be age-dependent : the efficiency was about 40% at birth but increased to 90% at 12-weeks old.

More References:

• Postic et al., J. Biol. Chem., 1999
• Postic et al., Genesis, 2000