脊髓性肌萎缩症患者神经元样细胞SMN2基因mRNA的表达  

The expression of SMN2 gene mRNA in neuron-like cells derived from patients with spinal muscular atrophy

作　　者：罗新明[1] 杨晓苏[1] 肖波[1] 

机构地区：[1]中南大学湘雅医院神经内科

出　　处：《中华内科杂志》2006年第10期831-834,共4页Chinese Journal of Internal Medicine

基　　金：国家自然科学基金(30170330);湖南省自然科学基金(02JJY3016)

摘　　要：目的检测脊髓性肌萎缩症(SMA)患者神经元样细胞 SMN2基因 mRNA 的表达。方法用 PCR-RFLP 的方法对 SMA 患者进行基因诊断,诱导其骨髓间充质干细胞分化为神经元样细胞,RT-PCR 和测序检测该细胞 SMN 2基因 mRNA 的表达,所有过程与对照组进行对比研究。结果SMN2基因的扩增产物为全长转录产物 fl-SMN mRNA(266 bp)和转录时跳过外显子7的产物 SMN△7mRNA(212 bp,经测序证实缺少的54 bp 为外显子7的序列);SMA 患者 fl-SMN mRNA 的表达占总表达量的23.2%,远低于对照者(占总表达量的82.0%);而 SMN△7 mRNA 表达占总表达量的76.8%,高于对照者的18.0%。结论 SMA 患者神经元样细胞的 SMN2基因转录时存在选择性剪接,即剪接时跳过外显子7,是导致其全长 SMN 蛋白不足的原因之一。Objective To detect the difference of SMN2 mRNA expression between the neuron-like cells（NLCs） derived from patients with spinal muscular atrophy （SMA）. Methods Polymerase chain reaction-restriction fragment length polymorphism （PCR-RFLP） was performed to diagnose the patients with SMA and the controls. Mesenchymal stem cells （MSCs） were induced into neuron-like cells which become the models of neurons. The transcripts of SMN2 were testified with RT-PCR combined with sequencing. Results Two bands（266 bp and 212 bp） were found in the gel picture of RT-PCR and the band of 266 bp was the full length transcript（ fl-SMN mRNA）. The band of 212 bp was testified by sequencing to be deletion of the exon 7, which was the production of alternative splicing （ skipping exon 7, SMNA7 mRNA）. The expression of fl-SMN mRNA accounted for 23.2% of the total SMN mRNA in the SMA patients, being much lower than the rate in the controls （82.0%）. In contrast, 76. 8% of SMN gene transcripts was SMNA7 mRNA in the SMA patients, being much higher than the rate of 18% in the controls. Conclusions Alternative splicing exists in SMN2 gene transcription, that is, exon 7 is skipped during the processing of SMN2 mRNA in the NLCs of SMA patients, which is one of the reasons of the full-length SMN protein lacking.

关 键 词：脊髓性肌萎缩症 基因 运动神经元 α 

分 类 号：R744[医药卫生—神经病学与精神病学]