Host and phage-coded functions required for coliphage N4 DNA replication

|April 15, 1986

Summary

Bacteriophage N4 DNA replication utilizes Escherichia coli DNA ligase and ribonucleotide reductase but not DNA polymerase I

Area of Science:

Background:

Bacteriophage N4 relies on host Escherichia coli machinery for its DNA replication.
Understanding host-bacterial interactions is crucial for phage biology.

Purpose of the Study:

To investigate the specific Escherichia coli DNA synthesis genes essential for bacteriophage N4 growth and DNA replication.
To identify the N4-encoded proteins involved in its DNA replication process.

Main Methods:

Utilized Escherichia coli strains with mutations in various DNA synthesis genes.
Assessed bacteriophage N4 growth and N4 DNA synthesis in mutant strains.
Examined the role of host DNA gyrase and DNA polymerase I activities.

Main Results:

N4 DNA synthesis is independent of E. coli dnaA, dnaB, dnaC, dnaE, dnaG, and rep genes.
N4 replication requires E. coli dnaF (ribonucleotide reductase) and lig (DNA ligase) gene products.
N4 DNA fragment processing requires the 5'-3' exonuclease activity, but not the polymerizing activity, of the E. coli polA gene product.
E. coli DNA gyrase activity is essential for N4 DNA synthesis.
Five N4 genes (dbp, dnp, dns, vRNAp, exo) are required for N4 DNA replication.

Conclusions:

Bacteriophage N4 DNA replication is a complex process involving specific host factors and viral-encoded proteins.
N4 utilizes a subset of E. coli DNA synthesis machinery, highlighting unique replication strategies.
Identified five novel N4 genes critical for its DNA replication, including a virion-associated RNA polymerase and a DNA polymerase.

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