Segmental localization of urea transporter mRNAs in rat kidney.
Segmental localization of urea transporter mRNAs in rat kidney.
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大鼠肾脏中尿素转运蛋白 mRNA 的节段定位。
DOI：
10.1152/ajprenal.1997.272.5.f654
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
Hediger,MA
中科院分区：
文献类型：
--
作者：
Shayakul,C;Knepper,MA;Smith,CP;DiGiovanni,SR;Hediger,MA
肾上皮细胞表达至少两种不同的尿素转运蛋白mRNA，称为UT 1和UT 2，它们通过选择性剪接来源于单个UT基因。以前的免疫定位研究使用的多克隆抗体，不区分这两个成绩单的蛋白质产物显示，尿素转运蛋白的表达仅限于内髓集合管和亨利氏袢的下降薄肢。为了确定这两个结构中的蛋白质表达的转录本，我们进行了逆转录-聚合酶链反应研究，使用UT 1和UT 2特异性引物的显微解剖结构。UT 1 mRNA仅在内髓集合管中检测到，与其作为加压素调节的尿素转运蛋白的鉴定一致。UT 2-mRNA在Henle氏短袢下降细肢的晚期和Henle氏长袢下降细肢的内侧髓部均有表达。这种定位与预测的UT 2在髓尿素再循环中的作用一致。因此，结合前述生理学研究，我们的数据表明，这些转运蛋白在尿浓缩机制中发挥核心作用。
Renal epithelia express at least two distinct urea transporter mRNAs, termed UT1 and UT2, that are derived from a single UT gene by alternative splicing. Previous immunolocalization studies using a polyclonal antibody that does not distinguish between the protein products of these two transcripts revealed that expression of urea transporter protein is restricted to inner medullary collecting ducts and descending thin limbs of Henle's loop. To identify which transcripts account for protein expression in these two structures, we carried out reverse transcription-polymerase chain reaction studies in microdissected structures using UT1- and UT2-specific primers. UT1 mRNA was detected only in the inner medullary collecting duct, consistent with its identification as the vasopressin-regulated urea transporter. In contrast, UT2-mRNA was detected in the late part of descending thin limbs of short loops of Henle and in the inner medullary part of descending thin limbs of long loops of Henle. This localization is consistent with the predicted role of UT2 in medullary urea recycling. Thus, in conjunction with foregoing physiological studies, our data indicate that these transporters play central roles in the urinary concentrating mechanism.