The transgene construct consists of the enhancer/promoter of the TTR gene, the mouse Igf1 cDNA, and the SV40t polyadenylation-signaling sequence. The IGF-I transgene was flanked with a tandem repeat of the HS4 chromosomal insulator sequence from the 5' region of the chicken beta-globin gene. This line carries approximately three copies of the transgene construct. This line expresses Igf1 at 3x the endogenous level in the liver. (J:129478)