Baek S J, Lee K D, Shen R F
Department of Obstetrics and Gynecology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
Gene. 1996 Sep 16;173(2):251-6. doi: 10.1016/0378-1119(95)00881-0.
Thromboxane synthase (TS) is a cytochrome P-450 (CYP450) enzyme catalyzing the conversion of prostaglandin endoperoxide (PGH2) into thromboxane A2 (TxA2) which plays a crucial role in hemostasis and cardiovascular diseases. Twelve genomic clones containing the DNA encoding the human TS gene (hTS) were isolated and characterized to determine the exon/intron boundaries and restriction maps of the nearly contiguous structure of the gene. The hTS contains 13 exons spanning more than 150 kb. Its first five exons, divided by relatively large introns, spread over 100 kb, but encode less than one third of the full-length TS transcript. Southern analysis indicates that the human haploid genome contains a single copy of the TS gene. Although multiple transcription start points (tsp) are utilized, transcription of hTS is primarily TATA-independent, as determined by promoter-directed reporter gene expression in transfected cells. A dinucleotide (CA) repetitive sequence identified in the ninth intron of the gene exhibits allelic polymorphism. At least four distinctive alleles, containing from 13 to 20 copies of the CA repeats, have been detected.
血栓素合酶（TS）是一种细胞色素P-450（CYP450）酶，可催化前列腺素内过氧化物（PGH2）转化为血栓素A2（TxA2），后者在止血和心血管疾病中起关键作用。分离并鉴定了12个包含编码人TS基因（hTS）的DNA的基因组克隆，以确定该基因近乎连续结构的外显子/内含子边界和限制性图谱。hTS包含13个外显子，跨越超过150 kb。其前五个外显子被相对较大的内含子隔开，分布在100 kb以上，但编码的全长TS转录本不到三分之一。Southern分析表明，人类单倍体基因组包含TS基因的单拷贝。尽管使用了多个转录起始点（tsp），但如在转染细胞中通过启动子指导的报告基因表达所确定的，hTS的转录主要不依赖于TATA。在该基因的第九个内含子中鉴定出的二核苷酸（CA）重复序列表现出等位基因多态性。已检测到至少四个不同的等位基因，包含13至20个拷贝的CA重复序列。
