DNA dependent RNA synthesis is inhibited by :

Rifampin binds to the subunit of bacterial DNA-dependent RNA polymerase and thereby inhibits RNA synthesis. Rifampin is bactericidal for mycobacteria. Ethambutol inhibits arabinosyl transferase III, thereby disrupting the transfer of arabinose into arabinogalactan biosynthesis, which in turn disrupts the assembly of mycobacterial cell wall. Colchicine inhibits the release of histamine-containing granules from mast cells, the secretion of insulin from pancreatic cells, and the movement of melanin granules in melanophores. Chloramphenicol acts primarily by binding reversibly to the 50S ribosomal subunit (near the binding site for the macrolide antibiotics and clindamycin, which chloramphenicol inhibits competitively). Although binding of tRNA at the codon recognition site on the 30S ribosomal subunit is undisturbed, the drug apparently prevents the binding of the amino acid-containing end of the aminoacyl tRNA to the acceptor site on the 50S ribosomal subunit. Ref :Gumbo T. (2011). Chapter 56. Chemotherapy of Tuberculosis, Mycobacterium Avium Complex Disease, and Leprosy. In L.L. Brunton, B.A. Chabner, B.C. Knollmann (Eds), Goodman & Gilman's The Pharmacological Basis of Therapeutics, 12e