PITX2 R62H突变导致角膜环状皮样瘤的分子基础  

Role of PITX2 R62H Mutation in Ring Dermoid of Cornea

作　　者：刘小平[1] 朱飞舟[1] 王果[1] 邓启盼[1] 张静[1] 李琼[1] 凌捷[1] 邬玲仟[1] 梁德生[1] 潘乾[1] 龙志高[1] 龚惠勇[1] 夏家辉[1] 张灼华[1] 夏昆[1] 

机构地区：[1]中南大学医学遗传学国家重点实验室,长沙410078

出　　处：《生物化学与生物物理进展》2008年第3期274-282,共9页Progress In Biochemistry and Biophysics

基　　金：国家自然科学基金资助项目(305002601);国家重点基础研究发展计划(973)资助项目(2004CB518800)~~

摘　　要：角膜环状皮样瘤(RDC)是一种呈常染色体显性遗传的角膜良性肿瘤,前期研究证明,PITX2基因的G185A突变(R62H)是导致RDC发生的原因.为了进一步探讨R62H导致RDC的分子基础,将PITX2构建至原核表达载体,诱导表达后纯化融合蛋白进行EMSA实验,显示R62H与DNA的结合能力并未明显下降.筛选稳定表达PITX2WT和R62H的HeLa细胞克隆,用流式细胞仪分析细胞周期,并用Quantitative Real-time PCR来检测细胞克隆的β-catenin和Cyclin D1的表达水平,结果发现稳定表达PITX2R62H的HeLa细胞的增殖活性低于PITX2WT,且β-catenin和CyclinD1的mRNA水平均比PITX2WT明显下降.由此推测,R62H突变使Wnt/β-catenin→PITX2信号途径发生改变,促使基因表达异常,导致细胞异常增生和角膜环状皮样瘤的形成.Ring dermoid of cornea （RDC） is an autosomal dominant disorder of cornea. The previous study identified a G185A mutation of PITX2 gene in a Chinese family with RDC. To investigate the pathological mechanism of PITX2 R62H mutation, a PITX2 prokaryotic expression plasmid were constructed and GST-PITX2 fusion protein were purified. EMSA was further conducted. The DNA-banding ability ofPITX2 R62H was similar to that of the wild type PITX2 were found. The cell lines stably expressed PITX2 was also generated, and cell cycle were analyzed by flow cytometry, and the expression of 13-catenin and Cyclin D1 were detected by quantitative Real-time PCR. The results showed that proliferating ability of cells expressing PITX2 R62H was lower than that of cells expressing PITX2 WT, as well as 13-catenin and Cyclin D1 mRNA level. These findings revealed that PITX2 R62H mutation affected the Wnt/β-catenin→PITX2 pathway, promoted the genes expressing abnormally, and led to abnormal cell proliferation and the formation of RDC, which may play an important role in pathogenesis of RDC.

关 键 词：角膜环状皮样瘤(RDC) PITX2 转录因子 Β-CATENIN CYCLIND1 

分 类 号：Q189[生物学—神经生物学]