Determination of the Type of Nucleic Acid in Rubella Virus using 5-Bromo-2′-deoxyuridine

Abstract

SALZMAN¹ showed that 5 - fluoro - 2′ - deoxyuridine (5-FUdR), when added to virus-tissue culture systems, specifically inhibited the synthesis of DNA viruses but did not affect RNA virus or protein synthesis. The inhibition could be reversed by the addition of excess thymidine. The use of 5-FUdR, or one of its analogues, thus provides an indirect test of whether a virus contains DNA or RNA. An advantage of such a test is its rapidity when compared with conventional techniques of nucleic acid isolation and purification; but in order to avoid misleading results the final concentration of the analogue² and the serum content of the tissue culture maintenance medium must be carefully controlled³. Media prepared with high concentrations of serum or embryo extract may contain enough thymidine to cause partial reversal of the inhibitory action of the analogue.