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目的 分离位于染色体 3p2 4 2 6区域中鼻咽癌新的抑瘤基因。方法 在染色体 3p2 4 2 6鼻咽癌杂合性丢失 (lossofheterogosity ,LOH)高频区 ,用RT PCR及Northern杂交检测了2 0个表达序列标记 (expressedsequencetag ,EST)在鼻咽癌细胞株HNE 1和原代培养的正常鼻咽上皮细胞中的表达水平 ,并对其中一个在鼻咽癌细胞株HNE 1中表达下调的EST在 19例鼻咽癌活检组织中的表达进行了检测。用cDNA文库筛选方法获得其全长cDNA序列 ,对该序列进行了初步分析。结果 获得一个位于染色体 3p2 5 3的新基因 ,命名为NAG 7基因。该基因在 2 6 3% (5 19)的鼻咽癌活检组织中表达下调。它全长 16 6 7bp ,其开放阅读框 (openreadingframe ,ORF)编码一个含 94个氨基酸的碱性蛋白质 ,分子量为 110 2 3 87道尔顿 ,预测为一跨膜蛋白质。它含有一蛋白激酶C磷酸化位点和肉豆蔻基位点。迄今为止 ,NAG 7基因序列在基因库中未见任何同源性基因。结论 NAG 7基因是一个在鼻咽癌中表达下调的新基因 ,它的改变可能参与了鼻咽癌的发生发展
Objective To isolate a new tumor suppressor gene of nasopharyngeal carcinoma in the region of chromosome 3p2 4 2 6. METHODS: Twenty overexpressed sequence tags (ESTs) were detected in the nasopharyngeal carcinoma cell line HNE 1 by RT PCR and Northern blot in the high frequency region of loss of heterozygosity (LOH) on chromosome 3p2 426, And primary cultured normal nasopharyngeal epithelial cells, and the expression of one of the ESTs downregulated in the nasopharyngeal carcinoma cell line HNE 1 in 19 NPC tissues was detected. The full-length cDNA sequence was obtained by cDNA library screening method, and the sequence was preliminary analyzed. Results A new gene located on chromosome 3p2 5 3 was obtained and named as NAG 7 gene. The gene was down-regulated in 263% (5 of 19) NPC tissues. It is 16 6 7 bp in length. Its open reading frame (ORF) encodes a basic 94 amino acid protein with a molecular weight of 110 2 387 Daltons and is predicted to be a transmembrane protein. It contains a protein kinase C phosphorylation site and a myristyl site. To date, no homologous gene has been found in the gene pool for the NAG 7 gene sequence. Conclusion NAG 7 gene is a new gene whose expression is down-regulated in nasopharyngeal carcinoma, and its alteration may be involved in the occurrence and development of nasopharyngeal carcinoma