Molecular cloning and primary structure of rat thyroxine-binding globulin.
Molecular cloning and primary structure of rat thyroxine-binding globulin.
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大鼠甲状腺素结合球蛋白的分子克隆和一级结构。
DOI：
10.1021/bi00236a012
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发表时间：
1991
期刊：
影响因子：
2.9
通讯作者：
Refetoff,S
中科院分区：
文献类型：
--
作者：
Imamura,S;Mori,Y;Murata,Y;Yamamori,I;Miura,Y;Oiso,Y;Seo,H;Matsui,N;Refetoff,S
摘要：大鼠甲状腺素结合球蛋白（TBG）cDNA从大鼠肝脏cDNA文库中分离，使用人TBG cDNA作为探针。从两个重叠的cDNA插入片段中，获得了1714个核苷酸的比对cDNA序列。在1526个核苷酸上与人TBG cDNA有70%的同源性。为了确认克隆的cDNA编码大鼠TBG和定位成熟分子的NH 2-末端氨基酸，通过亲和层析纯化蛋白质并进行直接蛋白质微测序。NH_2端氨基酸序列与核苷酸序列推断的氨基酸序列一致。大鼠TBG cDNA由截短的前导序列（35个核苷酸）、编码成熟蛋白的完整序列（1194个核苷酸）和3 '非翻译区（485个核苷酸）组成，其中含有两个多聚腺苷酸化信号。推测大鼠TBG由398个氨基酸组成（Afr= 44607），比人TBG多3个NH 2端残基，一级结构同源性为76%。在六个潜在的N-糖基化位点中，四个位于与人TBG相比保守的位置。大鼠肝脏的北方印迹分析显示约1.8-磷酸酶TBG mRNA。甲状腺切除后其含量显著增加，甲状腺素治疗后其含量呈剂量依赖性下降。
Revised Manuscript Received March 13, 1991 abstract: Rat thyroxine-binding globulin (TBG) cDNAs were isolated from a rat liver cDNA library by using a human TBG cDNA as a probe. From two overlapping cDNA inserts, an aligned cDNA sequence of 1714 nucleotides was obtained. There was 70% homology with human TBG cDNA over the span of 1526 nucleotides. In orderto confirm that the cloned cDNA encodes rat TBG and to localize the NH2-terminal amino acid of the mature molecule, the protein was purified by affinity chromatography and subjected to direct protein microsequencing. TheNH2-terminal amino acid sequence was identical with that deduced from the nucleotide sequence. The rat TBG cDNA sequenced consisted of a truncated leader sequence (35nucleotides), the complete sequence encodingthe mature protein (1194 nucleotides) and the 3'-untranslated region (485 nucleotides), containing two polyadenylation signals. It was deduced that rat TBG consists of 398 amino acids (Afr= 44607), three NH2-terminal residues more than human TBG, with which it shares 76% homology in primary structure. Of the six potential N-glycosylation sites, four are located in conserved positions compared to human TBG. Northern blot analysis of rat liver revealed an approximately 1.8-kilobase TBG mRNA. Its amount increased markedlyfollowing thyroidectomy and decreased with thyroxinetreatment in a dose-dependent manner.