Webb T E, Henderson D J, Roberts J A, Barnard E A
Molecular Neurobiology Unit, Royal Free Hospital School of Medicine, London, England.
J Neurochem. 1998 Oct;71(4):1348-57. doi: 10.1046/j.1471-4159.1998.71041348.x.
Degenerate PCR was used to amplify DNAs encoding members of the P2Y receptor family from rat brain RNA. A full-length sequence obtained for one novel clone (R5) contained an intronless open reading frame that encoded a polypeptide of 361 amino acids, sharing 84% sequence identity with the human P2Y4 receptor. When R5 was stably expressed in Jurkat cells, calcium fluxes resulting from stimulation of the receptor showed that UDP, ADP, 2-methylthio-ATP, and diadenosine tetraphosphate were inactive, whereas UTP and ATP were both full agonists with similar potency. At the human receptor, ATP has significantly lower potency than UTP. The R5 transcript was not detected in brain by northern hybridization. Therefore, its tissue distribution was assessed by PCR, and the mRNA was found to be widely distributed at a low abundance, being present in brain, spinal cord, and a variety of peripheral organs. Localization of the receptor transcript in adult rat brain sections by in situ hybridization indicated that it is expressed at highest levels in the pineal gland and ventricular system. It is presumed that R5 is a species orthologue of the human P2Y4 receptor but with this significant difference in agonist pharmacology.
简并PCR用于从大鼠脑RNA中扩增编码P2Y受体家族成员的DNA。获得的一个新克隆（R5）的全长序列包含一个无内含子的开放阅读框，其编码一个由361个氨基酸组成的多肽，与人类P2Y4受体的序列同一性为84%。当R5在Jurkat细胞中稳定表达时，受体刺激引起的钙流显示，UDP、ADP、2-甲硫基-ATP和二腺苷四磷酸无活性，而UTP和ATP都是具有相似效力的完全激动剂。在人类受体上，ATP的效力明显低于UTP。通过Northern杂交在脑中未检测到R5转录本。因此，通过PCR评估其组织分布，发现该mRNA以低丰度广泛分布，存在于脑、脊髓和各种外周器官中。通过原位杂交在成年大鼠脑切片中定位受体转录本表明，它在松果体和脑室系统中表达水平最高。推测R5是人类P2Y4受体的物种同源物，但在激动剂药理学上存在这一显著差异。
