一个编码XAP2同源蛋白的人视网膜cDNA的克隆

Cloning of a Retinal cDNA Encoding a XAP2 Homologous Protein

用同源筛选法从人视网膜ｃＤＮＡ分子库中克隆到一个与ＸＡＰ２ｃＤＮＡ有高度同源的ｃＤＮＡ序列，长１３８６ｂｐ，其第１７—１１７１ｎｔ为一个完整的开放阅读框（ＯＲＦ），编码３８４个氨基酸，其Ｃ端较ＸＡＰ２长５５个氨基酸；３ＵＴＲ长２１８ｂｐ，１３５５—１３６０ｎｔ为加尾信号序列ＡＡＴＡＡＡ，１３７７—１３８６ｎｔ为ＰｏｌｙＡ序列。由该ｃＤＮＡＯＲＦ推导的蛋白质被命名为ＡＩＰＨ，它在ＧｅｎＢａｎｋ的登录号为：ＡＦ０３８４３７。它与ＸＡＰ２的氨基酸一致率为４２％，相似率为６１．７％。计算机分析结果显示：推导的ＡＩＰＨ蛋白与乙肝病毒Ｘ蛋白（ＨＢＸ）有三个较高同源的区域。其中两个对应于ＨＢＸ的反式转录激活功能结构域。ＡＩＰＨｃＤＮＡ与人体１６种组织ｍＲＮＡ的Ｎｏｒｔｈｅｒｎ杂交结果显示：这个来源于视网膜的转录本也可在骨骼肌和心脏中见到，杂交带长度约１．９Ｋｂ；此外在骨骼肌和心脏及其它１４种组织中还可见到另一个长约５．

In this paper, a cDNA sequence having high homol ogy with the XAP2 cDNA has been cloned from human retinal cDNA library by homolo gous screening method. Within the length of 1386 bp, the cDNA contains a 1155bp( 17-1171nt) open reading frame encoding 384 amino acid residues. The C terminal region of this deduced protein has 55 amino acids more than XAP2 protein. In the 218bp of 3UTR, the location of 1355-1361nt is the predicted tailing signal se q uence “AATAAA” and a polyA lies in 1377-1386nt. The gene was mamed as AIPH wit h the Accession No.AF038437 in GenBank. The amino acid identity between AIPH and XAP2 is 42% and the similarity is 61.7%. The result analyzed by computer shows that the deduced AIPH protein has three homologous regions with hepatitis virus X protein(HBX), and two of them correspond to the trans transcript activity do mains of HBX. The northern blot analysis of mRNA from sixteen human tissues reve als that the cDNA from retinal can be detected with a 1.9kb transcript in skelet al muscle and heart, and another 5.8kb transcript can be detected in all 16 tiss ues.