外显子芯片对肌萎缩侧索硬化模型鼠腰髓组织的分析及机制探讨

Exon Array Analysis of Lumbar Spinal Cord from hSOD1 - G93A Transgenic Mice and Exploration of Pathogenesis

目的从基因表达水平和外显子选择性剪接水平探讨肌萎缩侧索硬化(amyotrophic lateral sclerosis,ALS)模型鼠(hSOD1-G93A基因型阳性小鼠)发病相关的基因和信号通路,分析症状前期转录水平的改变及可能的发病启动机制。方法筛选鉴定hSOD1-G93A基因型阳性雌性小鼠发病早期(30 d)做研究组(30A组),以同窝同龄SOD1-G93A基因型阴性雌性小鼠做对照组(30C组),应用Affymetrix小鼠外显子芯片检测小鼠腰髓组织的基因转录本及可变剪接事件,并对相关基因进行功能分类(gene ontology hierarchy analysis,GO分类)及生物学通路分析。结果在30A组和30C组两组比较中,基因表达谱水平仅有1个基因(未知基因)在30A组中表达高于30C组2倍以上,共有4个基因在30A组的表达高于30C组1.5倍以上,且仅有1个基因为已知基因(NM_030707)。未发现有1.5倍以上表达下调的基因。在外显子水平,共有85个发生选择性剪接的外显子,分别属于85个转录本,仅有36个已知基因。对NM_030707基因及36个可变剪接基因进行GO分析及通路分析,得出其功能及涉及的信号转导通路。结论与30C组相比,在基因表达水平,致病性hSOD1-G93A在ALS症状前期影响不大;在转录水平,发现了新的异常剪接基因。推测出现的新基因及新的异常剪接事件可能与hSOD1-G93A基因在症状前期致病性有关。

Objective To study the differential expression of genes and the amount of alternative exon splicing events in spinal cord samples of mouse model of ALS,which were in asymptomatic stage.The changes were analyzed in transcription levels of early stage in ALS,helping us to explore the possible initiator of ALS.Methods By using Affymetrix Mouse Exon 1.0ST arrays,we analyzed the transcription profiles of the lumbar spinal cord removed from three female SOD1-G93A mice（30-days of age） and three female non-transgenic littermates.By using MAS（Molecule Annotation System） systems,the biologi-cal significance of high-throughput experimental data were further discussed,such as the gene ontology（GO） hierarchy analysis and the pathway analysis.Results By comparing the 30A and 30C groups only 1 gene was identified upregulated more than 2-fold（definitely 2.8-fold） and 4 genes upregulated more than 1.5-fold.On exon level,85 PSRs（probe select regions） were identified as alternatively spliced exons that belonged to 85 ASTs（alternatively spliced transcripts）,and 36 transcripts have an-notation.Functions and related pathways of these genes were obtained.Conclusion Compared with the control group,pathogenic hSOD1-G93A gene has few significant effects on gene expression profiles in the early stage of ALS.On transcriptional level,no foregone alternative splicing event was found.The new gene and new alternative splicing event are presumably correlated with the pathogenic effect of hSOD1-G93A genes in the early stage of ALS.