Human urate oxidase gene: cloning and partial sequence analysis reveal a stop codon within the fifth exon

Using the cDNA and selected genomic probes of rat urate oxidase, we have screened the human genomic library and isolated seven clones; one clone (clone 13) contained exonic regions which correspond to the exons 5, 6, and 7 of rat urate oxidase gene. The nucleotide sequence was determined for these three exons and exon/intron junctions, and compared with the sequence from the rat gene. A mutation resulting in a stop codon TGA was found in the fifth exon of the human urate oxidase gene. Sequence analysis of the polymerase chain reaction amplified DNA, corresponding to the fifth exon of urate oxidase from DNA samples from four different individuals, confirmed the same TGA stop codon in all. This single stop codon mutation and/or other mutation(s) in this gene may be responsible for the lack of urate oxidase activity in the human.