Attenuation of virulence by distribution of the Mycobacterium tuberculosiserp gene

Tuberculosis is an infectious disease caused by the inhalation of mycobacte rial species belonging to the Mycobacterium tuberculosis complex, The patho genicity of these mycobacteria is associated to the ability of invade, surv ive and multiply within the macrophages of the host. The identification of the corresponding virulence genes would help to define targets for new anti -infective molecules and/or vaccine. In that context, we focused on protein s exported by M. tuberculosis, a class of molecules directly in contact wit h the host during tuberculosis. Thanks to a genetic screening, we identifie d the clp gene present in mycobacteria causing tuberculosis and leprosy, an d encoding a surface-exposed, repetitive protein. Disruption of the erp gen e in M. tuberculosis and Mycobacterium bovis BCG affects the multiplication of these mycobacteria both within macrophages in vitro and in mice, Our re sult suggest that erp contributes to the virulence of M. tuberculosis.