A novel stop codon mutation (X417L) of the ferrochelatase gene in bovine protoporphyria, a natural animal model of the human disease.
Protoporphyria (PP) is caused by a deficiency of ferrochelatase (FC) activity, which catalyzes the final step in the heme biosynthesis pathway. Bovine are the only species other than man with naturally occurring PP. For expression of the PP phenotype, two copies of the mutated gene are necessary in bovine, whereas one copy is sufficient in humans. We report the first potential disease-causing mutation in the bovine FC gene. The coding region of FC was sequenced from the liver tissue of protoporphyric and normal bovine. A transversion was identified at nucleotide position 1250 which changed the stop codon to leucine (TGA-->TTA) in the protoporphyric FC sequence. As a consequence, the mutant protein is predicted to have an additional 27 amino acids. To screen other bovine for the G-->T transversion, cDNAs from liver tissue of clinically and biochemically normal, and from heterozygous and homozygous affected animals were used for allele-specific polymerase chain reaction. Three normal animals had only the G allele, five affected animals had only the T allele, and three heterozygous animals had both the G and T alleles. These results support our hypothesis that this mutation causes PP in bovine.
Department of Medicine and Liver Center, University of Alabama at Birmingham, Basic Health Science Building 395, 1918 University Boulevard, Birmingham, AL 35294-0005, USA.
M M
MM
Jenkins
R D
RD
LeBoeuf
G R
GR
Ruth
J R
JR
Bloomer
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002417:Cattle; D002418:Cattle Diseases / Q000201:enzymology / Q000235:genetics*; D003001:Cloning, Molecular; D018388:Codon, Terminator; D018076:DNA, Complementary; D005294:Ferrochelatase / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D006801:Humans; D008099:Liver / Q000201:enzymology*; D008969:Molecular Sequence Data; D017354:Point Mutation; D017092:Porphyria, Erythropoietic / Q000201:enzymology / Q000235:genetics* / Q000662:veterinary*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry
D018388:Codon, Terminator; D018076:DNA, Complementary; D011994:Recombinant Proteins; D005294:Ferrochelatase