Identification of an IS6110 insertion site in plcD, the unique phospholipase C gene of Mycobacterium bovis.
The IS6110 repetitive element is present in multiple copies in most Mycobacterium tuberculosis complex bacteria, except for Mycobacterium bovis strains, which usually contain a single copy of IS6110 located on a 1.9 kb PvuII fragment of the direct repeat region. IS6110 transposition can disrupt coding regions and is a major force of genomic variation. In a previous work it was demonstrated that phospholipase C genes are preferential loci for IS6110 transposition in M. tuberculosis clinical strains. Bacterial phospholipase C enzymes participate in pathogenic mechanisms used by different organisms, and have been implicated in intracellular survival, cytolysis and cell-to-cell spread. Four phospholipase C genes (plcA, plcB, plcC and plcD) were detected in the genomes of M. tuberculosis, Mycobacterium africanum, Mycobacterium microti and 'Mycobacterium canettii'. M. bovis and the vaccine strain M. bovis Bacillus Calmette-Guérin contain only the plcD gene. In the present work, the existence of IS6110 insertions within plcD, the unique phospholipase C gene of M. bovis, has been investigated by PCR, Southern blot hybridization and sequencing analysis. In 18 (7.3 %) of 245 isolates analysed, the plcD gene was interrupted by the insertion of one copy of IS6110, which in all cases was transposed in the same orientation and at the same position, 1 972 894, relative to the genome of M. bovis AF2122/97. These 18 isolates were distributed in 6 different spoligotype patterns and contained 4 to 8 IS6110 copies. In contrast, strains showing an intact plcD gene contained one (87 %), two (9.4 %) or three (2.4 %) IS6110 copies, and only a single isolate (1.2 %) had four IS6110 copies. The implications of plcD gene disruption in M. bovis have not been fully investigated, but no differences in the organ distribution of the disease were detected when animals infected with strains from the same spoligotype patterns bearing plcD : : IS6110 and intact plcD were compared.
Viana-Niero
Cristina
C
Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, Rua Botucatu 862 3° andar, São Paulo, CEP 04023-062, Brazil.
Rodriguez
Cesar Alejandro Rosales
CAR
Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Professor Dr Orlando Marques de Paiva 87, São Paulo, CEP 05508-900, Brazil.
Bigi
Fabiana
F
Instituto de Microbiología y Zoología Agrícola del CICVyA - Instituto Nacional de Tecnología Agropecuaria (INTA), Castelar, Buenos Aires, Argentina.
Zanini
Marcos Santos
MS
Centro de Ciências Agrárias, Universidade Federal do Espírito Santo, PO Box 16, Alegre, Espírito Santo, Brazil.
Ferreira-Neto
José Soares
JS
Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Professor Dr Orlando Marques de Paiva 87, São Paulo, CEP 05508-900, Brazil.
Cataldi
Angel
A
Instituto de Microbiología y Zoología Agrícola del CICVyA - Instituto Nacional de Tecnología Agropecuaria (INTA), Castelar, Buenos Aires, Argentina.
Leão
Sylvia Cardoso
SC
Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, Rua Botucatu 862 3° andar, São Paulo, CEP 04023-062, Brazil.
D016172:DNA Fingerprinting; D004251:DNA Transposable Elements / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics; D005798:Genes, Bacterial / Q000235:genetics*; D014644:Genetic Variation; D009163:Mycobacterium bovis / Q000201:enzymology* / Q000235:genetics*; D016133:Polymerase Chain Reaction; D010738:Type C Phospholipases / Q000235:genetics*
D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D010738:Type C Phospholipases