标题：The Whole Structure of the Human Nonfunctional L-Gulono-γ-Lactone Oxidase Gene-the Gene Responsible for Scurvy-and the Evolution of Repetitive Sequences Thereon
期刊名称：Journal of Nutritional Science and Vitaminology
印刷版ISSN：0301-4800
电子版ISSN：1881-7742
出版年度：2003
卷号：49
期号：5
页码：315-319
DOI：10.3177/jnsv.49.315
出版社：Center for Academic Publications Japan
摘要：L-Gulono-γ-lactone oxidase (GULO), which catalyzes the last step of ascorbic acid biosynthesis, is missing in humans. The whole structure of the human gene homologue for this enzyme was disclosed by a computer-assisted search. Only five exons, as compared to 12 exons constituting the functional rat GULO gene, remain in the human genome. A comparison of these exons with those of their functional counterparts in rat showed that there are two single nucleotide deletions, one triple nucleotide deletion, and one single nucleotide insertion in the human sequence. When compared in terms of colons, the human sequence has a deletion of a single amino acid, two stop colons, and two aberrant colons missing one nucleotide besides many amino acid substitutions. A comparison of the remaining human exon sequences with the corresponding sequences of the guinea pig nonfunctional GULO gene revealed that the same substitutions from rats to both species occurred at a large number of nucleotide positions. From analyses of the molecular evolution of Alu sequences in the human GULO gene homologue, it is thought that two Alu sequences were inserted in the vicinity of a presumed position of lost exon 11 during the same period as GULO lost its function. It is predicted that six LINE-1 sequences located in and near the gene homologue were inserted not during that period.
