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.