Variable expression patterns of Mycobacterium tuberculosis PE-PGRS genes:: Evidence that PE-PGRS16 and PE-PGRS26 are inversely regulated in vivo

Evaluation of expression of 16 PE-PGRS genes present in Mycobacterium tuberculosis under various growth conditions demonstrated constitutive expression of 7 genes, variable expression of 7 genes, and no expression of 2 genes. An inverse expression profile for genes PE_PGRS16 and PE_PGRS26 was observed to occur in macrophages and in mice infected with M. tuberculosis. Variable expression of PE_PGRS proteins could have implications for their role in the immunopathogenesis of tuberculosis.