Individual Mycobacterium tuberculosis universal stress protein homologues are dispensable in vitro

• Published in: Tuberculosis (Edinburgh, Scotland) Vol. 90; no. 4; pp. 236 - 244
• Main Authors: Hingley-Wilson, S.M, Lougheed, K.E.A, Ferguson, K, Leiva, S, Williams, H.D
• Format: Journal Article
• Language: English
• Published: Scotland Elsevier Ltd 01.07.2010; Churchill Livingstone
• Subjects: Amino Acid Sequence; Animals; Antigens, Bacterial - genetics; Antigens, Bacterial - metabolism; Bacillus; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Carbon monoxide; Cell Hypoxia - genetics; Cell Hypoxia - physiology; Cell Line; Colony Count, Microbial; DosR; Gene Expression Regulation, Bacterial; Gene Knockout Techniques; Genes, Bacterial - physiology; Heat-Shock Proteins - genetics; Heat-Shock Proteins - metabolism; hspX; Humans; Hypoxia; Infectious Disease; Macrophages - microbiology; Mice; Molecular Aspects; Molecular Sequence Data; Mycobacterium tuberculosis - genetics; Mycobacterium tuberculosis - growth & development; Mycobacterium tuberculosis - metabolism; Phenotype; Pulmonary/Respiratory; Sequence Alignment; Stationary phase; Stress, Physiological - genetics; Tuberculosis - microbiology; Hypoxia; hspX; DosR; Stationary phase
• ISSN: 1472-9792; 1873-281X
• DOI: 10.1016/j.tube.2010.03.013

Summary Mycobacterium tuberculosis has 10 universal stress proteins, whose function is unknown. However, proteomic and transcriptomic analyses have shown that a number of usp genes are significantly upregulated under hypoxic conditions and in response to nitric oxide and carbon monoxide, as well as during M. tuberculosis infection of macrophage cell lines. Six of these USPs are part of the DosR regulon and this, along with their expression pattern and the phenotypes of usp mutants in other bacterial species, suggests a potential role in the persistence and/or intracellular survival of Mtb . Knock-out mutants of individual usp genes encoding the USPs Rv1996 , Rv2005c , Rv2026c and Rv2028c were generated and their growth and survival under hypoxic and other stress conditions examined. Although the majority of usp genes are highly induced in hypoxic conditions, mutation did not affect the long term survival of Mtb under these conditions, or in response to a range of stress conditions chosen to represent the environmental onslaughts experienced by the bacillus during an infection, nor during infection of mouse and human – derived macrophage cell lines. The possibility remains that these USPs are functionally redundant in Mtb.