PMID- 10074182
OWN - NLM
STAT- MEDLINE
DCOM- 19990506
LR  - 20200724
IS  - 0022-538X (Print)
IS  - 1098-5514 (Electronic)
IS  - 0022-538X (Linking)
VI  - 73
IP  - 4
DP  - 1999 Apr
TI  - The U69 gene of human herpesvirus 6 encodes a protein kinase which can confer 
      ganciclovir sensitivity to baculoviruses.
PG  - 3284-91
AB  - The protein encoded by the U69 open reading frame (ORF) of human herpesvirus 6 
      (HHV-6) has been predicted to be a protein kinase. To investigate its functional 
      properties, we have expressed the U69 ORFs from both HHV-6 variants, A and B, by 
      using recombinant baculoviruses (BV6AU69 and BV6BU69). Nickel agarose and 
      antibody affinity chromatography was used to purify the proteins to homogeneity 
      and when incubated with [gamma-32P]ATP, both U69 proteins became phosphorylated 
      on predominantly serine residues. These data strongly suggest that U69 is a 
      protein kinase which autophosphorylates. The phosphorylation reaction was optimal 
      at physiological pH and low NaCl concentrations. It required the presence of Mg2+ 
      or Mn2+, and Mg2+ was able to support phosphorylation over a wider range of 
      concentrations than Mn2+. Both ATP and GTP could donate phosphate in the protein 
      kinase assay and the former was more efficient. U69 was capable of 
      phosphorylating histone and casein (serine/threonine kinase substrates) but not 
      enolase (a tyrosine kinase substrate). For the autophosphorylation reaction, the 
      Michaelis constants for ATP of baculovirus-expressed HHV-6A and HHV-6B U69 were 
      calculated to be 44 and 11 microM, respectively. U69 is a homologue of the UL97 
      gene encoded by human cytomegalovirus which has been shown to phosphorylate the 
      antiviral drug ganciclovir (GCV). We analyzed whether the U69 ORF alone was 
      capable of conferring GCV sensitivity on baculoviruses BV6AU69 and BV6BU69. In 
      plaque reduction experiments, these baculoviruses displayed a GCV-sensitive 
      phenotype compared to a control baculovirus (BVLacZ). The 50% inhibitory 
      concentrations (IC50) of BV6AU69 and BV6BU69 were calculated to be 0.35 and 0.26 
      mM, respectively, whereas the control baculovirus had an IC50 of >1.4 mM. This 
      shows that the U69 gene product is the only one required to confer GCV 
      sensitivity on baculovirus.
FAU - Ansari, A
AU  - Ansari A
AD  - Department of Virology, Royal Free and University College Medical School, 
      University College London, Royal Free Campus, Hampstead, London NW3 2PF, United 
      Kingdom.
FAU - Emery, V C
AU  - Emery VC
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - J Virol
JT  - Journal of virology
JID - 0113724
RN  - 0 (Antiviral Agents)
RN  - EC 2.7.- (Protein Kinases)
RN  - P9G3CKZ4P5 (Ganciclovir)
SB  - IM
MH  - Antiviral Agents/*pharmacology
MH  - Baculoviridae/drug effects
MH  - Ganciclovir/*pharmacology
MH  - *Genes, Viral
MH  - Herpesvirus 6, Human/*drug effects/*genetics
MH  - Humans
MH  - Microbial Sensitivity Tests
MH  - Open Reading Frames/genetics
MH  - Protein Kinases/*genetics/metabolism
PMC - PMC104092
EDAT- 1999/03/12 00:00
MHDA- 1999/03/12 00:01
PMCR- 1999/04/01
CRDT- 1999/03/12 00:00
PHST- 1999/03/12 00:00 [pubmed]
PHST- 1999/03/12 00:01 [medline]
PHST- 1999/03/12 00:00 [entrez]
PHST- 1999/04/01 00:00 [pmc-release]
AID - 1640 [pii]
AID - 10.1128/JVI.73.4.3284-3291.1999 [doi]
PST - ppublish
SO  - J Virol. 1999 Apr;73(4):3284-91. doi: 10.1128/JVI.73.4.3284-3291.1999.