结核分枝杆菌复合体VNTR位点多态性与菌株MALDI-TOF MS蛋白谱差异的关系

  目的  研究结核分枝杆菌复合体(Mycobacterium tuberculosis complex, MTBC)数目可变串联重复序列(variable number tandem repeat, VNTR)重复单位拷贝数与菌株蛋白质谱差异的关系。  方法  采用多位点数目可变串联重复序列分析(multiple locus variable number tandem repeat analysis, MLVA)对MTBC进行基因分型。同时，利用基质辅助激光解析/电离飞行时间质谱(matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry, MALDI-TOF MS)对菌株的蛋白质谱进行主成分分析(principal components analysis，PCA)，分析VNTR位点重复单位拷贝数差异(多态性)与菌株PCA聚类的关系。  结果  共收集157株MTBC菌株。146株MTBC(质谱鉴定得分≥1.700)生成的PCA树状图分为3个群，分别为Ⅰ群(61株)、Ⅱ群(26株)和Ⅲ群(59株)。24个VNTR位点多态性存在差异，其中7个高、7个中等和10个低多态性。MTBC菌株的Mtub39、QUB26、QUB4156位点多态性与菌株MALDI-TOF MS聚类有关(P=0.000，P=0.035，P=0.017)。  结论  MTBC菌株的Mtub39、QUB26、QUB4156位点多态性与菌株蛋白质谱的差异有关，3个位点可能具有调控菌株蛋白质谱构成的作用。

Relationship Between the VNTR Loci Polymorphism and MALDI-TOF MS Protein Profile Diversity in Mycobacterium tuberculosis Complex

  Objective  To study the relationship between the copy numbers of repetitive units at variable number tandem repeat (VNTR) loci of Mycobacterium tuberculosis complex (MTBC) with its diversity of protein profiles.  Methods  The MTBC strains were subjected to genotyping using multiple locus variable number tandem repeat analysis (MLVA). Also, the principal component analysis (PCA) was performed for bacterial protein profiles of MTBC using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The relationship between the polymorphism of VNTR loci and PCA clustering was analyzed.  Results  A total of 157 MTBC strains were collected. 146 MTBC strains (MS identification score values ≥1.700) were performed PCA and three clusters, clusterⅠ(61 strains), clusterⅡ(26 strains) and cluster Ⅲ(59 strains), were generated. Polymorphic diversities were observed in 24 VNTR loci, among them, 7 were highly various, 7 were moderately, and 10 were low various. The polymorphism of Mtub39, QUB26 and QUB4156 loci were correlated with the results of MALDI-TOF MS clustering (P=0.000, P=0.035, P=0.017).  Conclusion  The polymorphism of Mtub39, QUB26 and QUB4156 loci in MTBC was correlated with the difference of MALDI-TOF MS protein profiles, suggesting that these loci may play a role in regulating the composition of protein profiles of MTBC strains.