Mathi S K, Chan J, Watt V M
Department of Physiology, University of Toronto, Ontario, Canada.
Endocrinology. 1995 Sep;136(9):4125-32. doi: 10.1210/endo.136.9.7649121.
A novel member of the insulin receptor family, the insulin receptor-related receptor (IRR), was initially identified by cloning genomic DNA homologous to the insulin receptor. We have now used Northern blot and polymerase chain reaction analyses of a variety of human tissues to demonstrate that the kidney is a major site of IRR gene expression. IRR transcripts (approximately 6 and approximately 2 kilobases) were detected only in human kidney by Northern blot analyses. Quantitative competitive polymerase chain reaction analysis revealed that IRR messenger RNA levels were distributed more widely. IRR transcripts in human kidney were approximately 3- to 10-fold greater than those in thymus, brain, heart, and stomach and approximately 150-fold higher than those in placenta, skeletal muscle, and liver. In situ hybridization histochemical analysis revealed that IRR transcripts were present in a subpopulation of cells within distal tubules of human kidney, beyond the most proximal segment of the distal convoluted tubule. In rat stomach, IRR messenger RNA was localized to a subset of neuroendocrine cells in gastric glands of the fundic mucosa. This selective distribution of IRR transcripts in human and rat tissues suggests that IRR may mediate the responses of a neuroendocrine factor involved in regulating select aspects of cell function in a highly tissue-specific manner.
胰岛素受体家族的一个新成员——胰岛素受体相关受体（IRR），最初是通过克隆与胰岛素受体同源的基因组DNA而被鉴定出来的。我们现在利用对多种人体组织进行的Northern印迹分析和聚合酶链反应分析，证明肾脏是IRR基因表达的主要部位。通过Northern印迹分析，仅在人体肾脏中检测到IRR转录本（约6千碱基和约2千碱基）。定量竞争性聚合酶链反应分析显示，IRR信使RNA水平分布更广泛。人体肾脏中的IRR转录本比胸腺、脑、心脏和胃中的转录本大约高3至10倍，比胎盘、骨骼肌和肝脏中的转录本大约高150倍。原位杂交组织化学分析显示，IRR转录本存在于人体肾脏远曲小管内的一部分细胞中，位于远曲小管最近端段之外。在大鼠胃中，IRR信使RNA定位于胃底黏膜胃腺中的一部分神经内分泌细胞。IRR转录本在人体和大鼠组织中的这种选择性分布表明，IRR可能以高度组织特异性的方式介导一种参与调节细胞功能特定方面的神经内分泌因子的反应。
