Raftogianis R B, Her C, Weinshilboum R M
Department of Pharmacology, Mayo Medical School/Mayo Clinic/Mayo Foundation, Rochester, MN 55905, USA.
Pharmacogenetics. 1996 Dec;6(6):473-87. doi: 10.1097/00008571-199612000-00001.
Sulfate conjugation catalysed by phenol sulfotransferase (PST) is an important pathway in the metabolism of many drugs. Two isoforms of PST have been characterized biochemically in human tissues-a thermostable (TS), or phenol-metabolizing (P) and a thermolabile (TL), or monoamine-metabolizing (M) form. Pharmacogenetic studies of TS and TL PST activities in the human blood platelet showed that the activities of these two isoforms were regulated by separate genetic polymorphisms. Subsequently, a series of TS PST cDNAs were cloned, and, based on sequence homology, those cDNAs could be classified as members of two separate subgroups, designated here as 'TS PST1' and 'TS PST2'-indicating the existence of three rather than two PST isoforms; TS PST1, TS PST2 and TL PST. The genes encoding TS PST2, STP2, and TL PST, STM, have been cloned, structurally characterized and mapped to chromosome 16-the same chromosome on which the TS PST1 gene, STP1, is localized. As a step toward molecular pharmacogenetic studies of sulfate conjugation in humans, we set out to clone and structurally characterize STP1, the remaining uncharacterized human PST gene. We found that STP1 spanned approximately 4.4 kb and contained 9 exons. The first two exons, IA and IB, were identified by performing 5'-rapid amplification of cDNA ends (RACE) with human liver cDNA as template. Exons IA and IB were noncoding and represented two different cDNA 5'-untranslated region sequences. No canonical TATA box sequences were present within the 5'-flanking regions of the gene, i.e. regions flanking exons IA and IB. Finally, use of the long polymerase chain reaction made it possible to determine that STP1 is located approximately 45 kb 5'-upstream from STP2 on the short arm of human chromosome 16. Cloning and structural characterization of STP1, when combined with knowledge of the structures of STP2 and STM, will make it possible to study the molecular basis for the genetic regulation of PST activity in human tissue.
由酚磺基转移酶（PST）催化的硫酸化结合反应是许多药物代谢的重要途径。在人体组织中，已对PST的两种同工型进行了生化特性鉴定——一种是耐热型（TS），即酚代谢型（P）；另一种是不耐热型（TL），即单胺代谢型（M）。对人体血小板中TS和TL PST活性的药物遗传学研究表明，这两种同工型的活性受不同的基因多态性调控。随后，一系列TS PST cDNA被克隆出来，基于序列同源性，这些cDNA可被归类为两个不同亚组的成员，在此命名为“TS PST1”和“TS PST2”——这表明存在三种而非两种PST同工型，即TS PST1、TS PST2和TL PST。编码TS PST2（STP2）和TL PST（STM）的基因已被克隆、进行了结构表征并定位到16号染色体上——TS PST1基因（STP1）也定位在这条染色体上。作为人类硫酸化结合反应分子药物遗传学研究的一步，我们着手克隆并对STP1（人类PST基因中尚未进行特性鉴定的剩余基因）进行结构表征。我们发现STP1跨度约为4.4 kb，包含9个外显子。前两个外显子IA和IB是通过以人肝脏cDNA为模板进行5'-cDNA末端快速扩增（RACE）鉴定出来的。外显子IA和IB是非编码的，代表两种不同的cDNA 5'-非翻译区序列。在该基因的5'-侧翼区域，即外显子IA和IB侧翼的区域，未发现典型的TATA框序列。最后，使用长链聚合酶链反应得以确定STP1位于人类16号染色体短臂上STP2上游约45 kb处。STP1的克隆和结构表征，与STP2和STM的结构知识相结合，将有可能研究人体组织中PST活性基因调控的分子基础。
