Human alpha_<1a>-adrenoceptor polymorphism : Association with benign prostate hyperplasia

分子克隆鉴定出三种不同的编码alpha_1-肾上腺素受体的cdna （alpha_<1a>, alpha_<1b>和alpha_<1d>）。在亚型中，人类前列腺已被证明主要表达α <1a>-肾上腺素受体，这些受体介导收缩反应。已知在人体内存在两个经Pst - I酶切的α <1a>-肾上腺素能受体基因的限制性片段长度多态性（RFLPs）。这种多态性可能赋予α <1a>-肾上腺素受体羧基末端额外的棕榈酰化位点，暗示异常的信号转导机制。此外，α <1a>-肾上腺素受体胞质第三环的突变可能诱导受体/信号转导的组成性激活。在本研究中，我们在α <1a>-肾上腺素能受体基因的第三个细胞内环中寻找可能的突变。27例患者在手术时获得新鲜前列腺组织，液氮冷冻，-80℃冷冻。从前列腺组织中提取总RNA，逆转录，制备cDNA。对编码α <1a>-肾上腺素能受体胞内第三环的PCR产物片段进行了纯化和DNA测序分析。结果显示，α <1a>-肾上腺素能受体基因的细胞质第三环未发生突变。此外，我们还研究了α <1a>-肾上腺素受体的Pst I-RFLP是否与女性尿道综合征有关。从基因组DNA中扩增出含有Arg492对应DNA序列的502 bp PCR产物，并在对照组和尿道综合征的中年女性中检测了经Pst I酶切为477bp和25bp的α _<1a>-肾上腺素能受体基因的2个RFLPs。日本尿道综合征患者α <1a>-肾上腺素能受体多态性频率与正常人无明显差异。然而，这种多态性的频率分布在正常的日本和美国人群中有显著差异。我们的初步研究没有提供任何证据来支持α <1a>-肾上腺素能受体基因多态性与蕨类神经性综合征之间的关联，然而，需要在日本和美国进行更大规模的研究。少

Molecular cloning identified three distinct cDNAs encoding alpha_1-adrenoceptors (alpha_<1a>, alpha_<1b>, and alpha_<1d>). Among subtypes, human prostate has been shown to express predominantly alpha_<1a>-adrenoceptors, and these mediate the contractile response. It is already known that two restriction fragment length poylmorphisms (RFLPs) of alpha_<1a>-adrenoceptor gene digested with Pst I restriction enzyme exist in human. This polymorphism might confer an additional putative palmitoylation site in the carboxy-terminal segment of alpha_<1a>-adrenoceptor, implying abnormal signal transduction mechanism. Also, mutation in the third cytoplas-mic loop of alpha_<1a>-adrenoceptor might induce the constitutive activation of the receptor/signal transduc-tion. In the present study, we looked for a possible mutation in the third intracellular loop of the alpha_<1a>-adrenoceptor gene. Fresh prostate tissues were obtained at the time of surgery from 27 patients, frozen in liquid nitrogen, and s … More tored at -80ﾟC.Total RNA was extracted from the prostate tissue, then reverse transcribed, and cDNA was prepared. Fragments of PCR products which encodes the third intracellular loop of alpha_<1a>-adrenoceptor were purified and analysed by DNA sequencer. As a result, no mutation in the third cytoplasmic loop of the alpha_<1a>-adrenoceptor gene was observed. Additionary, we examined whether the Pst I-RFLP of the alpha_<1a>-adrenoceptor is associated with female urethral syndrome. PCR product of 502 bp, which contains the DNA sequence corresponding to Arg492, has been amplified from genomic DNA, and 2 RFLPs of alpha_<1a>-adrenoceptor gene, which are digested with Pst I restriction enzyme into 477bp and 25 bp, were cheked in middle aged women of either control or urethral syndrome. The frequency of alpha_<1a>-adrenoceptor polymorphism was not differently distributed between patients with urethral syndrome and normal subjects in Japan. However, the frequency distribution of this polymorphism was significantly different between normal Japanese and U.S.populations. Our preliminary study does not provide any evidence to support an association between alpha_<1a>-adrenoceptor gene polymorphism and fern ale ure-thral syndrome, however, much larger studies of both Japan and U.S.are needed. Less