Characterization of the prv43 gene of pseudorabies virus and demonstration that it is not required for virus growth in cell culture.

We have determined the complete DNA sequence of the prv43 gene of a swine herpesvirus, pseudorabies virus. prv43 is 1119 bp in length with a G+C content of 74.5% and is predicted to encode a multiply hydrophobic protein with a molecular mass of 38 kDa. prv43 is colinear with the herpes simplex virus type 1 UL43 locus, and the prv43 and UL43 gene products are predicted to be 47% similar and 23% identical. prv43 is an early gene, producing a 1.2-kb transcript that is easily detected at 2 hr postinfection but not at 6 hr postinfection. We have constructed a prv43 deletion mutant that does not express a prv43 transcript. This mutant did not appear to be defective for viral growth and demonstrated that the gene is nonessential for virus growth in cell culture.