Aphidicolin, a tetracyclic diterpenoid, is an antibiotic with novel structure produced by the mold Cephalosporium aphidicola. Aphidicolin is an inhibitor of DNA polymerase-α .DNA polymerase-α is an enzyme complex involved in initiation of DNA replication and during synthesis of Okazaki fragments on the lagging strand. The DNA polymerase-α complex consists of 4 subunits: POLA1, POLA2, PRIM1, and PRIM2. POLA1 is the catalytic subunit. POLA2 is the regulatory subunit. PRIM1 and PRIM2 are the small and the large primase subunits .Aphidicolin selectively inhibited the activity of DNA polymerase-α without activity for DNA polymerase-β and mitochondrial DNA polymerase. Aphidicolin prevented cell division in sea urchin embryos . Aphidicolin was a potent inhibitor of cellular deoxyribonucleic acid synthesis. Aphidicolin strongly inhibited the growth of herpes simplex virus both in tissue culture and in the rabbit eye. Aphidicolin was active against iododeoxyuridine-resistant herpes virus . Aphidicolin showed antiviral activity and inhibited the incorporation of thymidine into DNA of cultured human embryonic lung cells. Aphidicolin (15 µg/ml) reduced the activity of crude and partially purified DNA polymerases from the cytosol .References: Ikegami S, TAGUCHI T, OHASHI M, et al. Aphidicolin prevents mitotic cell division by interfering with the activity of DNA polymerase-α[J]. Nature, 1978, 275(5679): 458-460. Lehman I R, Kaguni L S, Krause K H, et al. DNA polymerase alpha[J]. J. Biol. Chem, 1989, 264. Bucknall R A, Moores H, Simms R, et al. Antiviral effects of aphidicolin, a new antibiotic produced by Cephalosporium aphidicola[J]. Antimicrobial agents and chemotherapy, 1973, 4(3): 294-298. Ohashi M, Taguchi T, Ikegami S. Aphidicolin: a specific inhibitor of DNA polymerases in the cytosol of rat liver[J]. Biochemical and biophysical research communications, 1978, 82(4): 1084-1090.