甲状腺激素反应蛋白1基因—一个新的鼠脑甲状腺激素反应基因的克隆、表达分布及其功能预测

Cloning and studying on the expression and function of thyroid hormone-response protein-1 gene, a novel thyroid hormone-response gene from neonatal rat brain

目的 克隆新的大鼠脑甲状腺激素反应基因 ,研究其表达特征并初步预测其功能。方法建立先天性甲状腺功能减退 (甲减 )新生大鼠模型 ,用荧光标记的差异显示PCR(DD PCR)技术、亚克隆、测序及相似性检索获得未知的大鼠脑甲状腺激素反应基因的cDNA片段。采用电子克隆、RT PCR、测序并克隆其cDNA全长。经Northern印迹法证实其表达受到甲状腺激素的调节 ,并用半定量RT PCR方法和生物信息学技术观察其分布转录水平和预测其功能。结果 克隆了甲状腺激素反应蛋白 1(thyroidhormone responseprotein 1,TRP 1)基因全长cDNA ,共 973bp(基因登录号为AF3 4 83 65) ,在甲减新生大鼠的脑中 ,该基因的转录增强。该基因表达广泛 ,以脑组织中的表达水平最高 ;其在大鼠不同脑区的表达含量亦不同 ,以嗅脑最高。该基因的编码产物具有一些重要的结构域和功能基序。结论 TRP 1基因是新发现的甲状腺激素反应基因 ,它在正常的脑发育中可能具有重要的作用 ,其异常表达可能是甲减性脑发育障碍发生的分子机制之一。

Objective To is ol ate novel thyroid hormone-response genes, to study the characterizations of the ir expressions and to predict their possible functions in neonatal rats. Methods A neonatal rat model with congenital hypothyr oidism was established and cDNA fragments of novel thyroid hormone-response gen es from cerebral cortex of neonatal rats were obtained by fluorescence-labeled DD-PCR analysis, subcloning and sequencing. Complete cDNAs of novel thyroid hor mone-response genes were cloned by the techniques of electronic clone, RT-PCR and sequencing, their expressions regulated by thyroid hormone were confirmed b y Northern blot analysis, their distributions, transcription levels in different tissues and different brain areas were further observed by semiquantitative RT -PCR analysis, and their possible functions were postulated through bioinformat ic techniques. Results A novel complete cDNA of thyroid hormone-response protein-1 (TRP-1) gene is cloned. It is 973 bp in f ull-length (Gene Bank accession no. AF348365), and its transcription was enhanc ed in cerebral cortex in neonatal hypothyroidism rats. The expression of its mRN A was very extensive, but more abundant in brain. Its transcriptional level in d ifferent brain areas was not uniform, much higher in olfactory bulb. Its encodin g protein had some significant domains and motifs. Conclusion TRP-1 gene is a new thyroid hormone-response gene and may play an important role during normal brain development. Its abnormal expression may b e partially responsible for neurological defects in brain arising from thyroid h ormone deficiency during critical period for perinatal rats.