Biochemical Aspects of Variation in Foot-and-Mouth Disease Virus

Abstract

The biochemical basis for variation in foot-and-mouth disease virus (FMDV) was explored by analysis of the virus RNA and the virus-induced and structural proteins of 3 isolates of the virus. Two of the isolates were from serotype A and the 3rd was from serotype O. Hybridization studies of the RNA showed greater than 80% homology between the 2 type A viruses and about 65% homology between the 2 type A viruses and the virus of type O. The RNase T1 maps of the 3 viruses gave distinct patterns typical of FMDV, but did not show that any 2 of the 3 viruses were more closely related. The virus-induced primary translation products, P88, P52 and P100 isolated from infected [baby hamster kidney] cells, were compared by tryptic peptide analysis. Combinations of 3H- and 14C-leucine-labeled polypeptides were hydrolyzed with trypsin and resolved on an ion-exchange column. Much greater differences were found in P88 than in P52 or P100, indicating that the major variation occurs in the region of the genome coding for the structural proteins. Similar analysis of combinations of the structural proteins of the 3 viruses showed that there were differences in VP1, VP2 and VP3; these results were supported by those obtained by PAGE [polyacrylamide gel electrophoresis] analysis of the Staphylococcus aureus V8 protease cleavage products.