Figure 1.

Human leptin transgene and its expression pattern. A transgenic mouse expressing a leptin transgene was generated. The construct is shown at the bottom. The founder was bred into the C57BL/6J ob/ob background for six or more generations. Four groups were studied: ob/+, ob/+ TG, ob/ob, and ob/ob TG. A Northern blot of total RNA from tissues of ob/+ and ob/ob transgenic and nontransgenic mice was probed with a labeled human leptin cDNA fragment. A positive signal was detectable only in white adipose tissue of transgenic mice. The probe did not detect RNA in any tissues of the nontransgenic mice.