Haidar M A, Loya F, Yang Y, Lin H, Glassman A, Goldwasser E, Albitar M
Division of Laboratory Medicine, University of Texas M. D. Anderson Cancer Center, Houston 77030, USA.
J Struct Biol. 1997 Apr;118(3):220-5. doi: 10.1006/jsbi.1997.3842.
Regulated expression of the erythropoietin (EPO) gene in the adult kidney plays a key role in the regulation of erythropoiesis. However, uncertainty exists regarding the type of kidney cells involved in EPO gene expression. We previously showed by light microscopy that the lacZ reporter gene is expressed and inducible by hypoxia/anemia in the proximal convoluted tubular (PCT) cells of the kidneys of transgenic mice carrying the 5'-lacZ construct, in which the lacZ gene was placed downstream of a 7.0-kb mouse EPO gene segment containing 6.5 kb of the 5'-flanking sequence. We, report here the light and transmission electron microscopic examination of lacZ expression in the kidneys of transgenic mice carrying the 5'-lacZ construct and two additional constructs carrying the 6.5-kb 5'-flanking sequence with the body of the gene alone, or along with the 1.2-kb 3'-flanking sequence. The electron microscopic analyses unequivocally demonstrated that lacZ under the regulatory control of the 6.5-kb 5'-flanking sequence with or without the body of the gene and the 1.2-kb 3'-flanking sequence was expressed predominantly in the proximal convoluted tubular cells of the kidney following hypoxia induction.
促红细胞生成素（EPO）基因在成年肾脏中的调控表达在红细胞生成的调节中起关键作用。然而，关于参与EPO基因表达的肾细胞类型仍存在不确定性。我们之前通过光学显微镜观察发现，携带5'-lacZ构建体的转基因小鼠肾脏近端曲管（PCT）细胞中，lacZ报告基因可被缺氧/贫血诱导表达，该构建体中lacZ基因位于包含6.5 kb 5'侧翼序列的7.0 kb小鼠EPO基因片段下游。我们在此报告了对携带5'-lacZ构建体以及另外两个构建体（一个仅携带6.5 kb 5'侧翼序列与基因主体，另一个同时携带6.5 kb 5'侧翼序列、基因主体以及1.2 kb 3'侧翼序列）的转基因小鼠肾脏中lacZ表达的光学和透射电子显微镜检查结果。电子显微镜分析明确表明，在缺氧诱导后，受6.5 kb 5'侧翼序列调控（无论有无基因主体和1.2 kb 3'侧翼序列）的lacZ主要在肾脏近端曲管细胞中表达。
