分离与克隆中国人TPO基因片段及序列分析

Cloning and Sequence Analysis of Chinese Thrombopoietin Gene Fragment

应用ＲＴＰＣＲ技术从中国人胎肝细胞中分离出１个５６６ｂｐ大小的基因片段，经过克隆、限制性内切酶鉴定和序列分析证实为ＴＰＯ的ｃＤＮＡ片段．与ＧｅｎＢａｎｋ中发表的人ＴＰＯｍＲＮＡ的序列比较同源性在８２％～９９％之间，仅有２个碱基不相同，在１７５位密码子（５２３～５２５位的碱基）分别是ＣＧＧ和ＣＡＡ，即精氨酸（Ｒ）的位置上，中国人是谷胺酰氨（Ｇ）．而与测得的韩国人序列比较。

Thrombopoietin (TPO) is a recently identified hematopoietic growth factor that stimulates both megakaryopoiesis and thrombopoiesis through its interaction with a specific cell surface receptor encoded by the c mpl proto oncogene After decades of study, the regulation of this process is still not well understood, in particular those resulting from cancer chemo or irradiation therapy We isolated a cDNA fragment from mRNA of Chinese embryonic liver cells by means of reverse transcriptase polymerase chain reaction (RT PCR) then cloned and shown it to be TPO by DNA sequencing The cDNA sequence were compared to those of human TPO cDNA in the GenBank using the multiple sequence alignment program The results revealed that the N terminal sequences were considered more conservative than those in C terminal The alignment of the Chinese and previously described human TPO cDNA indicates that the degree of homology is between 82% to 99% identical One codon change was found at 175 (Arg Gln) in position bp 523 to 525 (CGG-CAA) of Chinese TPO cDNA relatively to L36052 sequence And a sequence differs from U59495 in same position (which is CAG), but it can be translate into the same amino acid with Chinese TPO.