Construction and phenotypic characterization of an auxotrophic mutant of Mycobacterium tuberculosis defective in L-arginine biosynthesis.
A mutant of Mycobacterium tuberculosis defective in the metabolism of L-arginine was constructed by allelic exchange mutagenesis. The argF mutant strain required exogenous L-arginine for growth in vitro, and in the presence of 0.96 mM L-arginine, it achieved a growth rate and cell density in stationary phase comparable to those of the wild type. The mutant strain was also able to grow in the presence of high concentrations of argininosuccinate, but its auxotrophic phenotype could not be rescued by L-citrulline, suggesting that the DeltaargF::hyg mutation exerted a polar effect on the downstream argG gene but not on argH. The mutant strain displayed reduced virulence in immunodeficient SCID mice and was highly attenuated in immunocompetent DBA/2 mice, suggesting that L-arginine availability is restricted in vivo.
Gordhan
Bhavna G
BG
MRC/NHLS/WITS Molecular Mycobacteriology Research Unit, School of Pathology, University of the Witwatersrand and the National Health Laboratory Service, Johannesburg, South Africa.
Smith
Debbie A
DA
Alderton
Heidi
H
McAdam
Ruth A
RA
Bancroft
Gregory J
GJ
Mizrahi
Valerie
V
D000818:Animals; D001120:Arginine / Q000096:biosynthesis / Q000502:physiology*; D004195:Disease Models, Animal; D007121:Immunocompetence; D007700:Kinetics; D051379:Mice; D008811:Mice, Inbred DBA; D016513:Mice, SCID; D016296:Mutagenesis; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000254:growth & development* / Q000472:pathogenicity; D009954:Ornithine Carbamoyltransferase / Q000235:genetics; D010641:Phenotype; D013379:Substrate Specificity; D014397:Tuberculosis, Pulmonary / Q000382:microbiology; D014774:Virulence
D001120:Arginine; D009954:Ornithine Carbamoyltransferase