Analysis of genetic polymorphisms affecting the four phospholipase C (plc) genes in Mycobacterium tuberculosis complex clinical isolates

Analysis of genetic polymorphisms affecting the four phospholipase C (plc) genes in Mycobacterium tuberculosis complex clinical isolates

Author Viana-Niero, C. Autor UNIFESP Google Scholar
Haas, P. E. de Google Scholar
van Soolingen, D. Google Scholar
Leao, S. C. Autor UNIFESP Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Natl Inst Publ Hlth & Environm
Abstract The Mycobacterium tuberculosis genome contains four highly related genes which present significant similarity to Pseudomonas aeruginosa genes encoding phospholipase C enzymes. Three of these genes, plcA, plcB and plcC, are organized in tandem (locus pIcABC). the fourth gene, plcD, is located in a different region. This study investigates variations in plcABC and plcD genes in clinical isolates of M. tuberculosis, Mycobacterium africanum and 'Mycobacterium canettii'. Genetic polymorphisms were examined by PCR, Southern blot hybridization, sequence analysis and RT-PCR. Seven M. tuberculosis isolates contain insertions of IS61 10 elements within plcA, plcC or plcD. in 19 of 25 M. tuberculosis isolates examined, genomic deletions were identified, resulting in loss of parts of genes or complete genes from the plcABC and/or plcD loci. Partial plcD deletion was observed in one M. africanum isolate. in each case, deletions were associated with the presence of a copy of the IS61 10 element and in all occurrences IS61 10 was transposed in the same orientation. A mechanism of deletion resulting from homologous recombination of two copies of IS61 10 was recognized in a group of genetically related M. tuberculosis isolates. Five M. tuberculosis isolates presented major polymorphisms in the plcABC and plcD regions, along with loss of expression competence that affected all four plc genes. Phospholipase C is a well-known bacterial virulence factor. the precise role of phospholipase C in the pathogenicity of M. tuberculosis is unknown, but considering the potential importance that the plc genes may have in the virulence of the tubercle bacillus, the study of isolates cultured from patients with active tuberculosis bearing genetic variations affecting these genes may provide insights into the significance of phospholipase C enzymes for tuberculosis pathogenicity.
Language English
Date 2004-04-01
Published in Microbiology-sgm. Reading: Soc General Microbiology, v. 150, p. 967-978, 2004.
ISSN 1350-0872 (Sherpa/Romeo, impact factor)
Publisher Soc General Microbiology
Extent 967-978
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000221067000023

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