Four tRNA-like sequences and a serpin homologue encoded by murine gammaherpesvirus 68 are dispensable for lytic replication in vitro and latency in vivo

Experimental infection of inbred strains of laboratory mice with murine herpesvirus 68 (MHV-68), a natural pathogen of wild rodents, results in acute productive infection of the lung followed by a latent infection of B lymphocytes. We have previously shown that MHV-68 encodes an open reading frame with similarity to poxvirus serpins, designated ORF1, and eight novel tRNA-like sequences. The latter are processed into mature, uncharged tRNAs and are abundantly expressed during both lytic and latent infection. In this study it is demonstrated that deletion of four of the tRNA-like sequences and ORF1 from the virus genome does not affect the ability of MHV-68 to replicate in vitro or to establish, and reactivate from, latency in vivo.