In vitro products of a membrane-free foot-and-mouth disease virus ribonucleic acid polymerase

Abstract

The foot-and-mouth disease virus-RNA polymerase complex was released from cytoplasmic membranes by the action of deoxycholate in the presence of dextran sulfate. The soluble polymerase complex synthesizes virus-specific RNA (37 S viral RNA, single-stranded; 20 S double-stranded RNA, and a RNA with heterogeneous sedimentation ( s) rate). Analysis of the final products of the “soluble polymerase complex” directly without use of deproteinizing agents showed both virus-specific RNA and a new component with s-rate in the 50 S region. This component contains infectious RNA and is not seen after deproteinization. In addition, it is stabilized by magnesium ion. Analysis of the “soluble polymerase complex” pulse labeled for 5 min with UTP- 3H in the cell-free system showed that the product (not deproteinized) was distributed in two s-rate classes, a 20–70 S and 100–300 S class. After deproteinization, all the RNA had an s-rate of less than 60 S. This RNA was heterogeneous in s-rate and it was partially resistant to ribonuclease. The 100–300 S component was concluded to be an intermediate in 37 S viral RNA synthesis and is postulated to be a complex of the polymerase with the replicative intermediate, or the so-called Franklin structure.