The alpha-fetoprotein (AFP) gene is transcribed at high levels in the fetal
liver and is repressed at birth, leading to low but detectable levels of A
FP mRNA in the adult liver. This repression is regulated, in part, by a loc
us that is unlinked to AFP called Alpha-fetoprotein regulator I (Afr1). Pre
vious studies showed that Afr1 regulation is independent of the AFP enhance
rs but requires the 1-kb AFP promoter/repressor region. Here, we demonstrat
e that a transgene with the 250-bp AFP promoter region linked to AFP enhanc
er element EII is expressed in the fetal liver and is postnatally repressed
. In addition, this transgene is regulated by Afr1. These data indicate tha
t the promoter is involved in postnatal AFP repression. Furthermore, we pro
vide a high-resolution map of the Afr1 locus on mouse chromosome 15. (C) 20
00 Academic Press.