脆性X综合征致病基因FMR1一个新型隐匿外显子发现及其鉴定  

Identification of a novel cryptic exon in intron 9 region of FMR1 gene among fragile X syndrome

作　　者：郭小艳[1] 富显果[1] 严爱贞[1] 廖娟[1] 张朵[1] 柯龙凤[1] 兰风华[1] 

机构地区：[1]南京军区福州总医院临床遗传与实验医学科,福建福州350025

出　　处：《国际检验医学杂志》2013年第1期6-8,共3页International Journal of Laboratory Medicine

基　　金：福建省科技计划重点资助项目(2010Y0045)

摘　　要：目的分析脆性X智力障碍1基因(FMR1基因)可变剪接表达类型。方法采用克隆-测序技术,从RNA途径分析人FMR1基因的可变剪接表达。结果构建健康人外周血cDNA53个T克隆,测序结果显示4个T克隆均有140bp大小的插入片段(NG_007529:21452-21591),为FMR1内含子9的一部分,生物信息学比对显示该片段上下游具有4个经典的剪接信号,可能为新的隐匿外显子。巢式PCR显示健康人多种组织cDNA中普遍存在该片段。杂种小基因剪接试验显示该片段可通过可变剪接,与上游的外显子9和下游的外显子10同时出现在体外培养真核细胞的成熟mRNA中。结论该研究发现人FMR1基因的新型隐匿外显子,丰富了人FMR1基因可变剪接的内容,也为进一步研究可变剪接与脆性X综合征发病机制之间的关系和脆性X智力障碍1蛋白的功能奠定了基础。Objective To analyze the expression of alternative splicing in fragile X mental retardation 1 gene（FMR1 gene）. Methods Clone-sequencing technology was used for the analysis of expression of human FMR1 gene. Results 53 T clones of peripheral blood cDNA of healthy subjects were constructed, among which 4 clones were confirmed to be with a 140 bp fragment, which was a part of intron 9（NG_007529：21452-21591） in FMR1 gene. Bioinformatics analysis indicated that there were four canonical splicing signals surrounding the 140 bp fragment, enabling it to be a novel cryptic exon. Nested PCR showed that this fragment was also present in the cDNA libraries of various tissues of healthy individual. Hybrid minigene splicing assay confirmed that the cytological behavior of the fragment was in complete agreement with an alternative exon. The inclusion of this alternative exon into the mature mRNA of human FMR1 would lead to the shift of reading frame downstream exon 9 and the appearance of premature stop codon 11 bases downstream exon 9.Conclusion The identification of this novel alternative exon could demonstrate that more complexity might exist in the alternative splicing of human FMR1 and shed new light on the function of fragile X metal retardation 1 protein, as well as the pathogenesis of fragile X syndrome.

关 键 词：FMR1基因 可变剪接 脆性X综合征 生物信息学 杂种小基因接剪实验 

分 类 号：R749.94[医药卫生—神经病学与精神病学]