Complete characterization of the 3 ' region of the human and mouse hereditary hemochromatosis HFE gene and detection of novel splicing forms

The human HFE gene was identified in 1996 as the gene whose mutations are r esponsible for hereditary hemochromatosis in most patients. Expression anal ysis by Northern blot indicated that the gene was approximately 4.1 kb in l ength. However, the cDNA reported was only 2716 bp. These results implied t hat at least 1.4 kb of the mRNA remained to be identified. In the present s tudy, we detected several 3' EST clones while screening the genomic region of the gene in search of potential additional HFE mRNA sequences. Subsequen t sequencing of these EST clones and RT-PCR experiments revealed that exon 7 of the HFE gene has, in fact, a length of 1944 bp and it presents two pol yadenylation signals. The new human HFE exon 7 region has been screened in non-C282Y HH patients in search for new putative mutations. Mouse 3' RACE e xperiments also further extend the previously reported mouse HFE exon 6 seq uence. Additionally, we report two novel end forms of the human HFE gene de tected by 3' RACE experiments and several novel splicing forms identified i n the HepG2 cell line. (C) 2001 Academic Press.