Toxic component of a type II toxin-antitoxin (TA) system. Has RNase activity (By similarity). Overexpression in M.tuberculosis or M.smegmatis inhibits colony formation in a bacteriostatic rather than bacteriocidal fashion. Its toxic effect is neutralized by coexpression with cognate antitoxin RelB (shown only for M.smegmatis). In combination with RelB represses its own promoter. Has been seen to bind DNA in complex with cognate antitoxin RelB but not alone. Interacts with cognate antitoxin RelB, which neutralizes the toxin. Also interacts with non-cognate antitoxin RelF in vitro, in M.smegmatis coexpression of these 2 genes increases the toxicity of RelE. Expressed in log phase cells (at protein level). Induced by rifampicin treatment. Expressed in human macrophages 110 hours after infection. Induced in the lungs of mice infected for 4 weeks. A member of the relBE operon. No visible phenotype in culture or upon infection of mice. Belongs to the RelE toxin family.