NPCEDRG基因是采用基因定位候选克隆策略获得的1个鼻咽癌候选抑瘤基因.NPCEDRG在鼻咽癌细胞和组织中表达下调,重新恢复NPCEDRG基因在CNE2细胞系的表达,可部分逆转CNE2的恶性表型.本研究对CNE2细胞所表达的NPCEDRG基因mRNA剪接变异体克隆、鉴定,发现NPCEDRG基因至少有7个转录起始位点,其中NM_032316的TSS位于ATG上游-85 nt处,AF538150和AK094248的TSS位于-25 nt处;AF538150不存在第2外显子中6核苷酸序列(3'-TTGCAG-3')的缺失,其CDs为516 bp,编码1种由171个氨基酸组成的蛋白质(而非GenBank中公布的CDs为510 bp,1种由169个氨基酸组成的蛋白质).本研究成功克隆得到1种新的NPCEDRG基因的mRNA剪接变异体V2,其TSS位于-23 nt处,其CDs为297 bp,编码1种由98个氨基酸组成的蛋白质.
NPCEDRG is an NPC associated gene discovered by positional cloning from the patients in Hunan province in southern China,which is localized at a region frequently linked to NPC susceptibility at 3p21.3.Here we have identified at least seven possible alternative splicing(AS) variants of NPCEDRG transcripts in CNE2 cells,encoding 3 protein isoforms consist of 213,171 and 98 amino acids(aa).Seven possible TSSs were determined by 5′-RACE.As previously reported,the TSSs of variants NM_032316 and AK094248 were located-85 and-25 nt upstream of the translation start site;and the TSS of variant AF538150 was located-25 nt and mapped 17 nucleotides downstream of the start of the NPCEDRG sequence.We found that AF538150 contained a 6-nucleotide sequence(5′-TTGCAG-3′) and was of 516 nucleotides encoding a 171 aa peptide.We also discovered a new TSS variant from-23 nt and encoding 98 aa by its 297 nucleotides.