A 9.2kb transgene containing the human IGFBP1 cDNA under the control of the mouse alpha-fetoprotein regulatory sequence was microinjected into the pronuclei of C57BL/6 x CBA F1 embryos. Four founder lines were established (2,3,4,16). Line 16 contains 8 copies of the transgene and expresses at high levels in fetal liver and yolk sac with lower levels of expression in gut epithelial cells and brain glial cells.