Human glutamate pyruvate transaminase (GPT): localization to 8q24.3, cDNA and genomic sequences, and polymorphic sites.
Human glutamate pyruvate transaminase (GPT): localization to 8q24.3, cDNA and genomic sequences, and polymorphic sites.
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DOI：
10.1006/geno.1996.4604
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发表时间：
1997-03
期刊：
影响因子：
4.4
通讯作者：
M. Sohocki;L. Sullivan;Wilbur Harrison;E. Sodergren;Frederick F.B. Elder;G. Weinstock;Sumio Tanase;S. Daiger
中科院分区：
文献类型：
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作者：
M. Sohocki;L. Sullivan;Wilbur Harrison;E. Sodergren;Frederick F.B. Elder;G. Weinstock;Sumio Tanase;S. Daiger
谷氨酸丙酮酸转氨酶（GPT）（E.C.2.6.1.2）的两种常见蛋白变体已被用作人类遗传标记超过二十年，尽管20世纪80年代GPT基因座的染色体定位产生了相互矛盾的结果。为了解决这一矛盾，并开发有用的DNA标记，该基因，我们分离和表征的cDNA和基因组克隆的GPT。我们已经明确映射人类GPT的末端8 q使用几种方法。首先，从8号染色体特异性文库中衍生出两个显示含有GPT序列的互补序列。其次，通过荧光原位杂交，我们将含有人GPT基因的粘粒定位到染色体8q24.3带。第三，我们将大鼠gpt cDNA定位于大鼠7号染色体的同线区。最后，特异于人GPT的PCR引物扩增包含在来自染色体8的长臂的“半YAC”内的序列，即，包含8 q端粒的YAC。人GPT基因组序列跨度为2.7 kb，由11个外显子组成，大小范围为79至243 bp。外显子序列编码495个氨基酸的蛋白质，其与先前报道的人GPT-1的蛋白质序列几乎相同。两种多态性GPT同工酶是密码子14中核苷酸取代的结果，编码GPT-1中的组氨酸和GPT-2中的天冬酰胺，这导致NlaIII限制性位点的获得或丧失。此外，含有GPT序列的粘粒还含有以前未定位的多态性微卫星序列D8 S421。克隆的GPT基因和相关多态性将有助于定位到8 q末端的疾病基因座的连锁和物理定位，包括非典型卵黄状黄斑营养不良（VMD 1）和Ogna型单纯性大疱性表皮松解症（EBS 1）。此外，这将是一个有用的系统，用于表征端粒区的8 q。最后，确定GPT同工酶变异的分子基础将允许基于PCR的检测这一全球性的多态性。
Two frequent protein variants of glutamate pyruvate transminase (GPT) (E.C.2.6.1.2) have been used as genetic markers in humans for more than two decades, although chromosomal mapping of the GPT locus in the 1980s produced conflicting results. To resolve this conflict and develop useful DNA markers for this gene, we isolated and characterized cDNA and genomic clones of GPT. We have definitively mapped human GPT to the terminus of 8q using several methods. First, two cosmids shown to contain the GPT sequence were derived from a chromosome 8-specific library. Second, by fluorescence in situ hybridization, we mapped the cosmid containing the human GPT gene to chromosome band 8q24.3. Third, we mapped the rat gpt cDNA to the syntenic region of rat chromosome 7. Finally, PCR primers specific to human GPT amplify sequences contained within a "half-YAC" from the long arm of chromosome 8, that is, a YAC containing the 8q telomere. The human GPT genomic sequence spans 2,7 kb and consists of 11 exons, ranging in size from 79 to 243 bp. The exonic sequence encodes a protein of 495 amino acids that is nearly identical to the previously reported protein sequence of human GPT-1. The two polymorphic GPT isozymes are the results of a nucleotide substitution in codon 14, coding for a histidine in GPT-1 and an asparagine in GPT-2, which causes a gain or loss of an NlaIII restriction site. In addition, a cosmid containing the GPT sequence also contains a previously unmapped, polymorphic microsatellite sequence, D8S421. The cloned GPT gene and associated polymorphisms will be useful for linkage and physical mapping of disease loci that map to the terminus of 8q, including atypical vitelliform macular dystrophy (VMD1) and epidermolysis bullosa simplex, type Ogna (EBS1). In addition, this will be a useful system for characterizing the telomeric region of 8q. Finally, determination of the molecular basis of the GPT isozyme variants will permit PCR-based detection of this world-wide polymorphism.