›› 2012, Vol. 32 ›› Issue (11): 1415-.doi: 10.3969/j.issn.1674-8115.2012.11.005

• Monographic report (Pathogenic microbiology) • Previous Articles     Next Articles

Research on relationship between polymorphisms of Mtub-39 and expression of downstream genes of Mycobacterium tuberculosis

ZHOU Ai-ping1,2, XU Zhi-hong1, SUN Qing1, YAO Yu-feng1, WU Xing-fu3   

  1. 1.Department of Medical Microbiology and Parasitology, Basic Medical College, Shanghai Jiaotong University, Shanghai 200025, China;2.Tibet University for Nationalities, Xianyang 712082, China;3.The Fifth People's Hospital of Suzhou, Suzhou 215007, China
  • Online:2012-11-28 Published:2012-11-30
  • Supported by:

    National Key Basic Research Development Program, “973” Program, 2009CB522605;National Natural Science Foundation of China, 31200109


Objective To analyse the 5 MIRU loci of Mycobacterium tuberculosis, and investigate the relationship between polymorphisms of MIRU loci and expression of downstream genes. Methods Bioinformatics method was used to predict the downstream genes promoter regions of 5 MIRU loci (ETR-C, Mtub-30, Mtub-39, MIRU-27 and MIRU-40). Promoter sequence was amplified by PCR, and was cloned into mycobacterial promoterless probe vector pMC210 to generate the recombinants. After confirmation by restriction endonuclease digestion and sequence analysis, the recombinant plasmids were transformed into mycobacterium smegmatis mc2155 by electroporation. The transcriptional level of reporter gene lacZ was evaluated by Real-Time PCR, and the influence of polymorphisms of MIRU loci on the expression of downstream genes was examined. Results Mtub-39 locus core region contained the promoter of the downstream gene. The recombinant plasmids harboring Mtub-39 locus with 1, 3 or 5 copy numbers were constructed. Real-Time PCR revealed that Mtub-39 locus with polymorphisms (pMC210-Mtub-39-N158, pMC210-Mtub-39-N139 and pMC210-Mtub-39-N146) had significant differences in the transcriptions of reporter gene lacZ (P=0.006 5). Conclusion The polymorphisms of Mtub-39 can significantly affect the promotor activity of the downstream genes, and sequentially regulate the expression of the gene.

Key words: Mycobacterium tuberculosis, mycobacterial interspersed repetitive units locus, pMC210, promoter