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Plasmid models for bacteriophage T4 DNA replication: requirements for fork proteins.

Publication ,  Journal Article
Benson, KH; Kreuzer, KN
Published in: J Virol
December 1992

Bacteriophage T4 DNA replication initiates from origins at early times of infection and from recombinational intermediates as the infection progresses. Plasmids containing cloned T4 origins replicate during T4 infection, providing a model system for studying origin-dependent replication. In addition, recombination-dependent replication can be analyzed by using cloned nonorigin fragments of T4 DNA, which direct plasmid replication that requires phage-encoded recombination proteins. We have tested in vivo requirements for both plasmid replication model systems by infecting plasmid-containing cells with mutant phage. Replication of origin and nonorigin plasmids strictly required components of the T4 DNA polymerase holoenzyme complex. Recombination-dependent plasmid replication also strictly required the T4 single-stranded DNA-binding protein (gene product 32 [gp32]), and replication of origin-containing plasmids was greatly reduced by 32 amber mutations. gp32 is therefore important in both modes of replication. An amber mutation in gene 41, which encodes the replicative helicase of T4, reduced but did not eliminate both recombination- and origin-dependent plasmid replication. Therefore, gp41 may normally be utilized for replication of both plasmids but is apparently not required for either. An amber mutation in gene 61, which encodes the T4 RNA primase, did not eliminate either recombination- or origin-dependent plasmid replication. However, plasmid replication was severely delayed by the 61 amber mutation, suggesting that the protein may normally play an important, though nonessential, role in replication. We deleted gene 61 from the T4 genome to test whether the observed replication was due to residual gp61 in the amber mutant infection. The replication phenotype of the deletion mutant was identical to that of the amber mutant. Therefore, gp61 is not required for in vivo T4 replication. Furthermore, the deletion mutant is viable, demonstrating that the gp61 primase is not an essential T4 protein.

Duke Scholars

Published In

J Virol

DOI

ISSN

0022-538X

Publication Date

December 1992

Volume

66

Issue

12

Start / End Page

6960 / 6968

Location

United States

Related Subject Headings

  • Virology
  • Recombinant Proteins
  • RNA Nucleotidyltransferases
  • Plasmids
  • Genome, Viral
  • Genes, Viral
  • Gene Deletion
  • Escherichia coli
  • DNA-Directed DNA Polymerase
  • DNA-Binding Proteins
 

Citation

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Benson, K. H., & Kreuzer, K. N. (1992). Plasmid models for bacteriophage T4 DNA replication: requirements for fork proteins. J Virol, 66(12), 6960–6968. https://doi.org/10.1128/JVI.66.12.6960-6968.1992
Benson, K. H., and K. N. Kreuzer. “Plasmid models for bacteriophage T4 DNA replication: requirements for fork proteins.J Virol 66, no. 12 (December 1992): 6960–68. https://doi.org/10.1128/JVI.66.12.6960-6968.1992.
Benson KH, Kreuzer KN. Plasmid models for bacteriophage T4 DNA replication: requirements for fork proteins. J Virol. 1992 Dec;66(12):6960–8.
Benson, K. H., and K. N. Kreuzer. “Plasmid models for bacteriophage T4 DNA replication: requirements for fork proteins.J Virol, vol. 66, no. 12, Dec. 1992, pp. 6960–68. Pubmed, doi:10.1128/JVI.66.12.6960-6968.1992.
Benson KH, Kreuzer KN. Plasmid models for bacteriophage T4 DNA replication: requirements for fork proteins. J Virol. 1992 Dec;66(12):6960–6968.

Published In

J Virol

DOI

ISSN

0022-538X

Publication Date

December 1992

Volume

66

Issue

12

Start / End Page

6960 / 6968

Location

United States

Related Subject Headings

  • Virology
  • Recombinant Proteins
  • RNA Nucleotidyltransferases
  • Plasmids
  • Genome, Viral
  • Genes, Viral
  • Gene Deletion
  • Escherichia coli
  • DNA-Directed DNA Polymerase
  • DNA-Binding Proteins