A human gene encodes a putative G protein-coupled receptor highly expressed in the central nervous system
A human gene encodes a putative G protein-coupled receptor highly expressed in the central nervous system
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DOI：
10.1016/s0169-328x(97)00336-7
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发表时间：
1998-02-01
期刊：
影响因子：
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通讯作者：
Battey, JF
中科院分区：
文献类型：
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作者：
Donohue, PJ;Shapira, H;Battey, JF
哺乳动物蛙皮素（bombesin，Bn）样神经肽受体包括胃泌素释放肽受体（gastrin-releasing peptide receptor，GRP-R）和神经介肽B受体（neuromedin B receptor，NMB-R），它们参与多种生理信号的调节，包括分泌、生长、肌肉收缩、趋化和神经调节等。我们已经使用逆转录-聚合酶链反应（PCR）分离的cDNA从人脑mRNA，GPCR/CNS，编码一个假定的G蛋白偶联受体（GPCR）的基础上存在的范式七个七螺旋跨膜结构域在其预测的氨基酸序列。GPCR/CNS的推导的蛋白质序列的分析表明，这种推定的受体是98%的相同最近报道的基因产物的推导的氨基酸序列和最低限度的相同性（类似于23%）的小鼠GRP-R和人内皮素-B（ET-B）受体。我们推导的蛋白质序列在12个位置上不同，分散在整个开放阅读框架，相对于原始序列。3.7 kb GPCR/CNS mRNA种类以组织特异性方式在体内表达，在脑和脊髓中检测到最高水平，在睾丸、胎盘和肝脏中发现较低水平，但在任何其他组织中未观察到可检测的表达。GPCR/CNS基因组克隆的分析揭示，人类基因包含一个长度约21 kb的内含子，其将编码区分成两个外显子并定位于人类染色体7 q31。在GPCR/CNS在成纤维细胞中稳定表达后，未观察到与对所有Bn受体亚型具有高亲和力的新鉴定的配体（DTyr（6）、β Ala（11）、Phe（13）、Nle（14）]Bn-（6-14））或Bn的特异性结合。在应用微摩尔水平的DPhe（6）、β Ala（11）、Phe（13）、Nle（14）]Bn-（6-14）或Bn（已知激活所有四种已知Bn受体亚型的浓度的激动剂）后，未观察到三磷酸肌醇升高。当GPCR/CNS在非洲爪蟾卵母细胞中表达时，尽管添加微摩尔水平的Bn肽激动剂，但未检测到钙依赖性氯离子通道的激活。我们的结论是，这种受体的天然配体是没有已知的天然存在的BN样肽和真正的激动剂GPCR/CNS仍有待阐明。(C)1998年Elsevier Science B.V.
The mammalian bombesin (Bn)-like neuropeptide receptors gastrin-releasing peptide receptor (GRP-R) and neuromedin B receptor (NMB-R) transduce a variety of physiological signals that regulate secretion, growth, muscle contraction, chemotaxis and neuromodulation. We have used reverse transcription-polymerase chain reaction (PCR) to isolate a cDNA from human brain mRNA, GPCR/CNS, that encodes a putative G protein-coupled receptor (GPCR) based upon the presence of the paradigmatic seven heptahelical transmembrane domains in its predicted amino acid sequence. Analysis of the deduced protein sequence of GPCR/CNS reveals this putative receptor to be 98% identical to the deduced amino acid sequence of a recently reported gene product and minimally identical (similar to 23%) to both murine GRP-R and human endothelin-B (ET-B) receptor. Our deduced protein sequence differs at 12 positions, scattered throughout the open reading frame, relative to the original sequence. A 3.7 kb GPCR/CNS mRNA species is expressed in vivo in a tissue-specific manner, with highest levels detected in brain and spinal cord, lower levels found in testis, placenta and liver, but no detectable expression observed in any other tissue. Analysis of GPCR/CNS genomic clones reveals that the human gene contains one intron that is about 21 kb in length that divides the coding region into two exons and maps to human chromosome 7q31. No specific binding is observed with either a newly identified ligand (DTyr(6),beta Ala(11),Phe(13),Nle(14)]Bn-(6-14)) having high affinity for all Bn receptor subtypes or Bn after GPCR/CNS is stably expressed in fibroblasts. No elevation in inositol trisphosphate is observed after the application of micromolar levels of either DPhe(6),beta Ala(11),Phe(13),Nle(14)]Bn-(6-14) or Bn, a concentration of agonist known to activate all four known Bn receptor subtypes. When GPCR/CNS is expressed in Xenopus oocytes, no activation of the calcium-dependent chloride channel is detected despite the addition of micromolar levels of Bn peptide agonists. We conclude that the natural ligand for this receptor is none of the known naturally occurring Bn-like peptides and the true agonist for GPCR/CNS remains to be elucidated. (C) 1998 Elsevier Science B.V.