U L 27.5 Is a Novel γ 2 Gene Antisense to the Herpes Simplex Virus 1 Gene Encoding Glycoprotein B

Abstract

An antibody made against the herpes simplex virus 1 U S 5 gene predicted to encode glycoprotein J was found to react strongly with two proteins, one with an apparent M r of 23,000 and mapping in the S component and one with a herpes simplex virus protein with an apparent M r of 43,000. The antibody also reacted with herpes simplex virus type 2 proteins forming several bands with apparent M r s ranging from 43,000 to 50,000. Mapping studies based on intertypic recombinants, analyses of deletion mutants, and ultimately, reaction of the antibody with a chimeric protein expressed by in-frame fusion of the glutathione S -transferase gene to an open reading frame antisense to the gene encoding glycoprotein B led to the definitive identification of the new open reading frame, designated U L 27.5. Sequence analyses indicate the conservation of a short amino acid sequence common to U S 5 and U L 27.5. The coding sequence of the herpes simplex virus U L 27.5 open reading frame is strongly homologous to the sequence encoding the carboxyl terminus of the herpes simplex virus 2 U L 27.5 sequence. However, both open reading frames could encode proteins predicted to be significantly larger than the mature U L 27.5 proteins accumulating in the infected cells, indicating that these are either processed posttranslationally or synthesized from alternate, nonmethionine-initiating codons. The U L 27.5 gene expression is blocked by phosphonoacetate, indicating that it is a γ 2 gene. The product accumulated predominantly in the cytoplasm. U L 27.5 is the third open reading frame found to map totally antisense to another gene and suggests that additional genes mapping antisense to known genes may exist.