克隆人胸腺素α原cDNA及RNA二级结构分析和带Xa因子的融合表达

Cloning of prothymosin α cDNA,analysis of RNA secondary structure and fusion expression with Xa factor

目的：克隆表达具有重要生物功能的胸腺素α原ｃＤＮＡ（ｈｕｍ ａｎ ｐｒｏｔｈｙｍ ｏｓｉｎα， ｈｕＰＴＭＡα）。方法：从健康中国人ＰＢＭＣｐｏｌｙ（Ａ）＋ ＲＮＡ中采用ＲＴ－ＰＣＲ法克隆ｈｕＰＴＭＡαｃＤＮＡ，并作ＲＮＡ二级结构分析。结果：克隆出长度为３００ ｂｐ，编码１００ 个氨基酸的ｈｕＰＴＭＡαｃＤＮＡ，经氨基酸序列分析发现在３７～４１ 位缺失Ａｓｎ３７ －Ｇｌｙ３８ －Ａｓｎ３９ －Ａｌａ４０－Ｇｌｕ４１ 和６５～６８ 位缺失Ｇｌｕ６５－Ｇｌｕ６６ －Ｇｌｕ６７ －Ｇｌｕ６８ ，与国际基因库连接检索证明是与ｈｕＰＴＭＡα有８６．４％ 同源性的一个新亚型，融合表达蛋白的相对分子质量为３．７×１０４，有促进ＩＦＮ和ＴＮＦ产生的生物学活性。结论：本研究克隆的ｈｕＰＴＭＡαｃＤＮＡ是中国人中新发现的一个多态型基因序列，它的克隆并表达成功为今后该基因的免疫功能研究及中国人基因型研究分析提供了有用的材料。

Objective: To clone and express human prothymosin α (huPTMAα) which has important biological functions. Methods: A huPTMA α cDNA was cloned from poly(A) + RNA of the healthy Chinese peripheral blood monocyte cells by RT PCR and the RNA second structure was analysed. Results: A huPTMA α cDNA sequence of 300 bp coding 100 amino acids was cloned. Two deletion domains were found. One was Asn 37 Gly 38 Asn 39 Ala 40 Glu 41 , the other was Glu 65 Glu 66 Glu 67 Glu 68 . It was a new subtype of huPTMA α and has 86.4% homology with GenBank data. The molecular weight 3.7×10 4 fusion protein bond was shown by SDS PAGE, also, an increased TNF and IFN production bioactivity was found. Conclusion: A new huPTMAα multitype sequence is identified from Chinese people. This material might be useful in studying immunology function and Chinese gene type.