摘要
目的克隆人神经母细胞瘤(Neuroblastoma,NB-1)细胞河豚毒抵抗型(TTX-R)Nav1.5Na+通道编码基因Nav1.5/SCN5A。方法使用逆转录聚合酶链反应(RT-PCR)方法,对NB-1细胞TTX-R Nav1.5Na+通道α亚单位编码基因Nav1.5/SCN5A进行克隆。结果人神经母细胞瘤Nav1.5Na+通道编码基因Nav1.5/SCN5A命名为hNbR1,其开放阅读框架可编码2016个氨基酸残基。序列分析显示其与心肌Nav1.5/SCN5A基因(hH1)编码的氨基酸相似性达99.1%;在DⅠ/SS1-SS2之间,存在一个半胱氨酸(c373)残基,提示hNbR1为TTX-RNa+通道;DⅠS3-S4之间一个位于第3号染色体的新的外显子(第6A外显子)编码了该通道α亚单位。另外,一个删除了DⅡ-Ⅲ之间第18外显子的选择性剪接体(hNbR1-2)被发现。结论 Nav1.5/SCN5A基因新的变构体参与编码神经肿瘤组织Nav1.5Na+通道,同时发现该基因的一个新外显子参与编码该通道,且发现Nav1.5/SCN5A基因比以往所知具有更加广泛的表达。
Objective Tetrodotoxin-resistant （TTX-R） voltage-gated Na＋ channel Nav1.5 is expressed in human neuroblastoma （NB-1） cells, but the gene encoding the TTX-R Na＋ channel is not identified. The aim of this study is to clone this gene. Methods The TTX-R Nav1.5 channel α subunit was cloned from NB-1 cells by RT-PCR. Results Two cDNAs encoding the TTX-R Na＋ channel α subunit in NB-1 cells were isolated and designated as hNbR1 and hNbR1-2 respectively. hNbR1-2 is an alternative splicing variant and characterized by a deletion of exon 18 in the intracellular loop between domainⅡ and Ⅲ. The longest open reading frame of hNbR1 encodes 2016 acid residues. The presence of a cysteine residue （c373） in the pore region domainⅠsuggests that these two channels are resistant to TTX. Sequence comparisons indicate that hNbR1 is highly homologous（99.1% amino acids identification） to human cardiac SCN5A except the region between domain ⅠS3 and S4 where is the exon 6A located in chromosome 3. Conclusion Nav1.5/SCN5A is widely distributed more than previously reported in which exists a new exon encoding the TTX-R sodium channel α-subunit in neural tumor tissues.
出处
《解剖科学进展》
CAS
2010年第4期350-353,356,共5页
Progress of Anatomical Sciences
基金
辽宁省自然基金(No20082110)
辽宁省教育厅基金资助项目(No05L500)
