锁骨颅骨发育不良家系致病基因突变及蛋白结构变化

摘要

目的：检测一个锁骨颅骨发育不良综合征（ CCD ）家系RUNX2基因突变情况，分析突变体蛋白结构的变化。方法对家系患者进行X线片检查，抽取外周静脉血，提取基因组DNA，采用聚合酶链反应（ PCR）扩增RUNX2基因并测序，对测序结果进行Blast分析。运用Swiss-Model软件预测， SWISS-Pdb、 Ras-Mol浏览器分析突变体蛋白构像。结果 CCD家系患者RUNX2基因编码序列在外显子3发生错义突变c.674 G＞T （p.R225L）。蛋白结构预测分析显示，突变体蛋白由于亲水性精氨酸为疏水性的亮氨酸所替代，引起分子内部分氢键基团丢失以及分子表面静电势能改变。结论 RUNX2基因c.674G＞T （p.R225L）杂合突变是该家系发病的分子基础，氨基酸序列的改变对蛋白质的空间结构产生影响。%Objective To identify the RUNX2 gene mutation in one family with cleidocranial dysplasia (CCD), and to analyze protein model of the mutation of RUNX 2 gene.Methods Radiological examination was performed , and the peripheral venous blood of the patients was collected .Genomic DNA was extracted , and the RUNX2 gene was ampli-fied by polymerase chain reaction (PCR).DNA sequences were analyzed with the Blastn program .The protein structures of the mutant RUNX2 gene were predicted by Swiss-Model software and viewed in SWISS-Pdb, and RasMol Viewer .Re-sults A heterozygous missense mutation c.674G>T ( p.R225L) in exon 3 of the RUNX2 gene was detected in this family.The mutant RUNX2 gene lost some intra-molecular hydrogen bond , and electrostatic potential energy on molecular surface.Conclusion RUNX2 gene heterozygous mutations c.674G>T (p.R225L) is the molecular basis for pathogene-sis of this family .The change of amino acid sequence influences the structure of protein .