Iodination of herpesvirus nucleic acids

A simple method is described for the iodination of herpes simplex virus (HSV) DNA. The procedure involved synthesis of 125-I-labeled 5-iodo-dCTP which was subsequently used as a precursor for the in vitro repair synthesis of HSV DNA. Synthesis of 5-iodo-dCTP and purification from oxidation and reduction reagents, buffer salts, unreacted dCTP and Na125-I was accomplished in a single chromatographic step. It was possible to prepare 125-I-labeled HSV DNA in vitro with specific activities exceeding 10-8 counts/min/mu-g. The DNA prepared by this method reassociated with DNA extracted from HSV-infected HEp-2 cells but not with HEp-2 cell DNA. Iodinated HSV DNA was susceptible to S-1-endonuclease digestion once denatured but was resistant to digestion in the native form. This method was used to synthesize 125-I-labeled ribo-CTP (5-iodo-CTP) which was used to prepare cytomegalovirus-specific complementary RNA. The method should be of value in the preparation of viral probes and for use in autoradiography of viral nucleic acids.