title: Vaccinia virus F16 protein, a predicted catalytically inactive member of the prokaryotic serine recombinase superfamily, is targeted to nucleoli.
abstract: The F16L gene of vaccinia virus (VACV) is conserved in all chordopoxviruses except avipoxviruses. The crocodile poxvirus F16 protein ortholog has highly significant similarity to prokaryotic serine recombinases and contains all amino acids that comprise the catalytic site. In contrast, F16 orthologs encoded by other poxviruses show only marginally significant similarity to serine recombinases, lack essential amino acids of the active site and are most likely inactive derivatives of serine recombinases. Nevertheless, the conservation of F16L in non-avian poxviruses suggested an important function. However, a VACV mutant with the F16L gene knocked out replicated normally in dividing and quiescent cells. The F16 protein was synthesized early after infection and detected in virus cores. When expressed in infected or uninfected cells, F16 accumulated in nucleoli depending on the level of expression and confluency of cells. Evidence was obtained that F16 forms multimers, which might regulate concentration-dependent intracellular localization.
authors.affiliation: Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Tatiana G
authors.initials: TG
authors.lastname: Senkevich
authors.forename: Eugene V
authors.initials: EV
authors.lastname: Koonin
authors.forename: Bernard
authors.initials: B
authors.lastname: Moss
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002466:Cell Nucleolus / Q000737:chemistry*; D002522:Chlorocebus aethiops; D055786:Gene Knockout Techniques; D006801:Humans; D008969:Molecular Sequence Data; D055503:Protein Multimerization; D045522:Recombinases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014616:Vaccinia virus / Q000201:enzymology / Q000502:physiology*; D019562:Viral Load; D010948:Viral Plaque Assay; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication
chemical_list: D045522:Recombinases; D014764:Viral Proteins