A G-->A substitution in an HNF I binding site in the human alpha-fetoprotein gene is associated with hereditary persistence of alpha-fetoprotein (HPAFP).
A family displaying hereditary persistence of alpha-fetoprotein (HPAFP) in adult life was detected in an antenatal screening programme for spina bifida. RFLP linkage analysis shows that the trait is linked with the albumin-AFP locus. The molecular mechanism responsible for the post-natal repression of the AFP gene is unknown. We wished to determine the molecular mechanism underlying HPAFP in this family. Sequence analysis of the 5'-flanking sequences of their gene revealed a GA substitution at position -119 associated with the trait. This substitution occurs in a potential HNF I binding site, and increases the similarity of the sequence to a consensus HNF I recognition site. In a competitive gel retardation assay the mutant sequence binds HNF I alpha more tightly than the wild type sequence. Furthermore, 5'-flanking sequences of the human AFP gene containing the G-->A substitution direct a higher level of CAT expression in transfected human hepatoma cells than the wild type sequences. We conclude that the G-->A substitution at position -119 of the AFP gene is the mutation causing HPAFP in this family. These results highlight the importance of this HNF I binding site in the developmental regulation of the AFP gene.
McVey
J H
JH
Haemostasis Research Group, Clinical Research Centre, Harrow, UK.
Michaelides
K
K
Hansen
L P
LP
Ferguson-Smith
M
M
Tilghman
S
S
Krumlauf
R
R
Tuddenham
E G
EG
D000328:Adult; D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics; D004247:DNA / Q000235:genetics* / Q000378:metabolism; D004252:DNA Mutational Analysis; D015870:Gene Expression; D006801:Humans; D008969:Molecular Sequence Data; D017354:Point Mutation; D011401:Promoter Regions, Genetic; D000509:alpha-Fetoproteins / Q000235:genetics* / Q000378:metabolism
D000509:alpha-Fetoproteins; D004247:DNA; D015500:Chloramphenicol O-Acetyltransferase