Chordopoxvirus protein F12 implicated in enveloped virion morphogenesis is an inactivated DNA polymerase.
Through the course of their evolution, viruses with large genomes have acquired numerous host genes, most of which perform function in virus reproduction in a manner that is related to their original activities in the cells, but some are exapted for new roles. Here we report the unexpected finding that protein F12, which is conserved among the chordopoxviruses and is implicated in the morphogenesis of enveloped intracellular virions, is a derived DNA polymerase, possibly of bacteriophage origin, in which the polymerase domain and probably the exonuclease domain have been inactivated. Thus, F12 appears to present a rare example of a drastic, exaptive functional change in virus evolution.


METHODS
This article was reviewed by Frank Eisenhaber and Juergen Brosius.
Natalya
N
Yutin
Guilhem
G
Faure
National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA. koonin@ncbi.nlm.nih.gov.
Eugene V
EV
Koonin
Arcady R
AR
Mushegian
D000595:Amino Acid Sequence; D018147:Chordopoxvirinae / Q000235:genetics*; D004259:DNA-Directed DNA Polymerase / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D019143:Evolution, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D014771:Virion / Q000378:metabolism
D014764:Viral Proteins; D004259:DNA-Directed DNA Polymerase