de la Peña P, Delgado L M, del Camino D, Barros F
Departamento de Biología Funcional, Area de Bioquímica, Facultad de Medicina, Universidad de Oviedo, Spain.
J Biol Chem. 1992 Dec 25;267(36):25703-8.
Two cDNA clones encoding two different isoforms of the thyrotropin-releasing hormone receptor (TRH-R) from GH3 rat anterior pituitary cells have been isolated. One isoform corresponds to the TRH-R(412) receptor previously described (de la Peña, P., Delgado, L. M., del Camino, D., and Barros, F. (1992) Biochem. J. 284, 891-899). The second one, named TRH-R(387), contains a 52-base pair deletion, which yields a new variant of the receptor protein 25 amino acid shorter and which contains 12 new residues on its carboxyl terminus. This new isoform is produced by alternative splicing of a retained intron in the primary transcript of a gene represented only once in the rat genome. Furthermore, the perfect colinearity between genomic DNA and TRH-R(412) cDNA demonstrates that no other introns are present within the coding region of the TRH receptor gene. Functional expression in Xenopus laevis oocytes indicates that both cDNAs encode fully functional TRH receptors. Otherwise, indistinguishable electrophysiological responses to TRH are evoked in oocytes expressing both receptor isoforms.
已从GH3大鼠垂体前叶细胞中分离出两个编码促甲状腺激素释放激素受体（TRH-R）两种不同亚型的cDNA克隆。其中一种亚型对应于先前描述的TRH-R(412)受体（德拉佩尼亚，P.，德尔加多，L.M.，德尔卡米诺，D.，和巴罗斯，F.（1992年）《生物化学杂志》284，891 - 899）。第二个克隆命名为TRH-R(387)，包含一个52个碱基对的缺失，这产生了一种受体蛋白的新变体，其长度短25个氨基酸，并且在其羧基末端含有12个新残基。这种新亚型是由大鼠基因组中仅出现一次的基因初级转录本中保留的内含子的可变剪接产生的。此外，基因组DNA与TRH-R(412) cDNA之间的完美共线性表明TRH受体基因的编码区域内不存在其他内含子。在非洲爪蟾卵母细胞中的功能表达表明这两个cDNA都编码功能完全的TRH受体。否则，在表达两种受体亚型的卵母细胞中会引发对TRH难以区分的电生理反应。
