Nucleic Acids of Measles and Vesicular Stomatitis Viruses

Abstract

Measles virus is classified as a myxovirus on the basis of its structure and cytopathic effect in tissue cultures(1,2,3), and therefore was tentatively assumed to be an RNA virus although the nature of its nucleic acid had not been established. Because 5-fluorode-oxyuridine (FUDR) inhibits the synthesis of DNA viruses(4,5,6), it can be used to differentiate RNA and DNA viruses. This report on the effect of FUDR on production of virus by an established line of cercopithecus monkey kidney cells (BS-C-1) (7), provides indirect evidence that measles actually is an RNA virus, and incidentally that vesicular stomatitis virus (VSV) is also an RNA virus.

A culture of the Edmonston strain of measles virus adapted to HeLa cells was used to inoculate 6 tubes containing monolayers of BS-C-1 cells. As assayed in the same cell line, the virus concentration of the inoculum was 10^4.5ID₅₀ per tube. At time of inoculation the cell count was approximately 2 × 10⁵ per monolayer. The medium used for virus growth and maintenance was Hanks'balanced salt solution containing 0.1% lac-talbumin hydrolysate, 0.16% NaHCO³, and 2% horse serum. In 3 of the 6 tubes the medium also contained 0.5 γ of FUDR per ml (2 × 10⁻⁶ m).

Each experiment included control cultures infected with (a) adenovirus type 3, as a known DNA virus; (b) the Leon strain of type 3 poliovirus, as a known RNA virus; and, because poliovirus is ether resistant while measles virus is ether sensitive, (c) VSV as an ether sensitive virus which we assumed to be an RNA virus until a survey of the literature revealed no proof of this. The adenovirus concentration, as assayed by BS-C-1 cells, was 10²ID₅₀ per tube. The poliovirus concentration, as assayed in primary monkey kidney cells, was 10^7.5 plaque-forming units per tube. The VSV concentration, as assayed in BS-C-1 cells, was 10^6.5ID₅₀ per tube.