Human cytomegalovirus UL47 tegument protein functions after entry and before immediate-early gene expression

J Virol. 2002 Feb;76(3):1043-50. doi: 10.1128/jvi.76.3.1043-1050.2002.

Abstract

The human cytomegalovirus UL47 open reading frame encodes a 110-kDa protein that is a component of the virion tegument. We have constructed a cytomegalovirus mutant, ADsubUL47, in which the central portion of the UL47 open reading frame has been replaced by two marker genes. The mutant replicated to titers 100-fold lower than those for wild-type virus after infection at either a high or a low input multiplicity in primary human fibroblasts but was substantially complemented on cells expressing UL47 protein. A revertant virus in which the mutation was repaired, ADrevUL47, replicated with wild-type kinetics. Mutant virions lacked UL47 protein and contained reduced amounts of UL48 protein. The mutant was found to be less infectious than wild-type virus, and a defect very early in the replication cycle was observed. Transcription of the viral immediate-early 1 gene was delayed by 8 to 10 h. However, this delay was not the result of a defect in virus entry or of the inability of virion proteins to transactivate the major immediate-early promoter. We also show that the UL47 protein coprecipitated with the UL48 and UL69 tegument proteins and the UL86-encoded major capsid protein. We propose that a UL47-containing complex is involved in the release of viral DNA from the disassembling virus particle and that the loss of UL47 protein causes this process to be delayed.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Capsid / genetics
  • Capsid / physiology*
  • Cells, Cultured
  • Cytomegalovirus / genetics
  • Cytomegalovirus / growth & development
  • Cytomegalovirus / metabolism*
  • Fibroblasts / cytology
  • Gene Expression*
  • Genes, Immediate-Early*
  • Genes, Viral
  • Humans
  • Immediate-Early Proteins / genetics*
  • Membrane Fusion / physiology
  • Mutagenesis
  • Precipitin Tests
  • Transcription, Genetic
  • Viral Proteins / physiology*
  • Virion / metabolism

Substances

  • IE1 protein, cytomegalovirus
  • Immediate-Early Proteins
  • UL47 protein, cytomegalovirus
  • Viral Proteins