Steiner F Zumsteg A Vogt B Ackermann M Schwyzer M 2010 Bovine herpesvirus 1 (BoHV-1) and BoHV-5 are closely related (82% amino acid identity) but differ strongly in neuropathogenesis. The immediate-early gene for BICP0 is less conserved (70% amino acid identity) and may contribute to a dissimilar phenotype. A peculiar difference is a guanosine hexamer in the BICP0-1 gene which aligns with only five guanosines in the BICP0-5 gene and therefore results in a frameshift in the latter open reading frame. Thus, the C-terminal amino acid sequence (residues 643-676 of BICP0-1 vs. 655-720 of BICP0-5) is completely different. We introduced the BICP0-5 frameshift into the BoHV-1 genome cloned as a bacterial artificial chromosome (BoHV-1 BAC) using the Red recombination system with galK selection and counterselection. Transfection of MDBK cells with the resulting BAC produced recombinant virus that replicated like wild type BoHV-1 in vitro. Attempts to exchange the entire BICP0-1 gene by the BoHV-5 homolog using the same approach failed repeatedly. Therefore, we cotransfected purified BICP0(-)/galK(+)-BoHV-1 BAC DNA with a recombination plasmid coding for BICP0-5 with or without a HA tag into MDBK cells. BoHV-1 recombinants expressing the respective proteins were characterized. In vitro, all recombinants grew to similar titers as the parental viruses, which demonstrates that BICP0-5 compensates for the growth defect of BICP0(-)/galK(+)-BoHV-1 and functionally complements BICP0-1 of BoHV-1. We conclude that BICP0 may be suitable to positively select BoHV-1 recombinants with deletions or insertions of additional genes of interest. application/pdf https://sonar.ch/global/documents/179763 eng info:eu-repo/semantics/altIdentifier/doi/10.1016/j.vetmic.2010.02.012 info:eu-repo/semantics/altIdentifier/pmid/20211531 info:eu-repo/semantics/openAccess Veterinary microbiology. - 2010 Animals Cattle Cell Line Chromosomes, Artificial, Bacterial Frameshift Mutation Genetic Complementation Test Herpesvirus 1, Bovine Herpesvirus 5, Bovine Humans Immediate-Early Proteins Recombination, Genetic Trans-Activators Transfection Ubiquitin-Protein Ligases Viral Proteins Bovine herpesvirus 5 BICP0 complements the bovine herpesvirus 1 homolog. http://purl.org/coar/resource_type/c_6501