title: VP1u phospholipase activity is critical for infectivity of full-length parvovirus B19 genomic clones.
abstract: Three full-length genomic clones (pB19-M20, pB19-FL and pB19-HG1) of parvovirus B19 were produced in different laboratories. pB19-M20 was shown to produce infectious virus. To determine the differences in infectivity, all three plasmids were tested by transfection and infection assays. All three clones were similar in viral DNA replication, RNA transcription, and viral capsid protein production. However, only pB19-M20 and pB19-HG1 produced infectious virus. Comparison of viral sequences showed no significant differences in ITR or NS regions. In the capsid region, there was a nucleotide sequence difference conferring an amino acid substitution (E176K) in the phospholipase A2-like motif of the VP1-unique (VP1u) region. The recombinant VP1u with the E176K mutation had no catalytic activity as compared with the wild-type. When this mutation was introduced into pB19-M20, infectivity was significantly attenuated, confirming the critical role of this motif. Investigation of the original serum from which pB19-FL was cloned confirmed that the phospholipase mutation was present in the native B19 virus.
authors.affiliation: Hematology Branch, National Heart, Lung, and Blood Institute, National Institute of Health, Bethesda, MD 20892, USA.
authors.forename: Claudia
authors.initials: C
authors.lastname: Filippone
authors.forename: Ning
authors.initials: N
authors.lastname: Zhi
authors.forename: Susan
authors.initials: S
authors.lastname: Wong
authors.forename: Jun
authors.initials: J
authors.lastname: Lu
authors.forename: Sachiko
authors.initials: S
authors.lastname: Kajigaya
authors.forename: Giorgio
authors.initials: G
authors.lastname: Gallinella
authors.forename: Laura
authors.initials: L
authors.lastname: Kakkola
authors.forename: Maria
authors.initials: M
authors.lastname: Söderlund-Venermo
authors.forename: Neal S
authors.initials: NS
authors.lastname: Young
authors.forename: Kevin E
authors.initials: KE
authors.lastname: Brown
mesh_terms: D000595:Amino Acid Sequence; D036022:Capsid Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002648:Child; D003001:Cloning, Molecular; D016679:Genome, Viral; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D016732:Parvovirus B19, Human / Q000201:enzymology / Q000235:genetics / Q000472:pathogenicity*; D054467:Phospholipases A2 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017422:Sequence Analysis, DNA
chemical_list: D036022:Capsid Proteins; C095547:capsid protein VP1, parvovirus B19; D054467:Phospholipases A2