Yamada M, Mori M
First Department of Internal Medicine, Gunma University.
Nihon Rinsho. 1999 Mar;57(3):737-45.
We measured amounts of thyrotropin-releasing hormone receptor (TRHR) mRNA in human pituitary tumors, and found a novel transcript of the TRHR gene. Competitive PCR revealed expression of the TRHR mRNA in all pituitary adenomas examined, and its level was variable and similar to that in the normal pituitary. When the C-terminal region was amplified by PCR, an additional short product was observed. Cloning and sequence analysis of this short fragment revealed that the deleted sequence corresponded exactly to the 5' sequence of exon 3, indicating alternative splicing of the TRHR mRNA. This alternative splicing resulted in a frame shift yielding a C-terminal truncated protein (HTRHR2) on translation. The mRNA ratio of the HTRHR2 versus the wild-type was significantly different among pituitary tumors.
我们检测了人类垂体瘤中促甲状腺激素释放激素受体（TRHR）mRNA的含量，发现了TRHR基因的一种新转录本。竞争性PCR显示，在所检测的所有垂体腺瘤中均有TRHR mRNA表达，其水平存在差异，且与正常垂体中的水平相似。当通过PCR扩增C末端区域时，观察到一个额外的短产物。对该短片段进行克隆和序列分析发现，缺失的序列与外显子3的5'序列完全对应，表明TRHR mRNA存在可变剪接。这种可变剪接导致了移码，在翻译时产生了一种C末端截短的蛋白质（HTRHR2）。在垂体瘤中，HTRHR2与野生型的mRNA比例存在显著差异。
