Farman N, Corthesy-Theulaz I, Bonvalet J P, Rossier B C
Département de Biologie, Centre d'Etudes Nucléaires de Saclay, Institut National de la Santé et de la Recherche Médicale U 246, Gif-sur-Yvette, France.
Am J Physiol. 1991 Mar;260(3 Pt 1):C468-74. doi: 10.1152/ajpcell.1991.260.3.C468.
The expression of the three alpha-isoforms of Na(+)-K(+)-adenosine triphosphatase (ATPase) was examined in rat brain and rat kidney by Northern blot analysis. All three isoforms were detected in brain tissue while alpha 1-isoform was observed in whole kidney, suggesting that either this isoform was solely expressed in this organ or that alpha 2- and/or alpha 3-isoforms were not detected only because of their restricted distribution among a minority of specialized tubular cells. To distinguish between these two possibilities, in situ hybridization with rat alpha 1-, alpha 2-, and alpha 3-ATPase cRNA was performed on rat kidney sections. Results show that alpha 1-isoform expression largely predominates in the loop of Henle, distal tubule, and cortical collecting tubule. The labeling was drastically reduced by preincubation of sections with RNase. A sense cRNA probe, used as control, did not hybridize. With alpha 2- and alpha 3-probes, the labeling was low and uniformly distributed. In contrast, these two isoforms were clearly expressed in the brain, together with alpha 1. We conclude that only alpha 1-isoform of the Na(+)-K(+)-ATPase is detectable along the rat nephron. Its expression predominates in the tubular segments known to have a high Na(+)-K(+)-ATPase activity.
通过Northern印迹分析检测了大鼠脑和大鼠肾中钠钾-三磷酸腺苷酶（ATP酶）三种α-同工型的表达。在脑组织中检测到了所有三种同工型，而在整个肾脏中观察到了α1-同工型，这表明要么这种同工型仅在该器官中表达，要么α2-和/或α3-同工型未被检测到仅仅是因为它们在少数特化的肾小管细胞中分布受限。为了区分这两种可能性，对大鼠肾脏切片进行了大鼠α1-、α2-和α3-ATP酶cRNA的原位杂交。结果显示，α1-同工型的表达在亨氏袢、远曲小管和皮质集合管中占主导。用核糖核酸酶预孵育切片后，标记显著减少。用作对照的正义cRNA探针未杂交。使用α2-和α3-探针时，标记较低且分布均匀。相比之下，这两种同工型与α1一起在脑中清晰表达。我们得出结论，沿大鼠肾单位仅可检测到钠钾-ATP酶的α1-同工型。其表达在已知具有高钠钾-ATP酶活性的肾小管节段中占主导。
