Genetic specificity of DNA synthesized in the absence of T4 bacteriophage gene 44 protein.

Upon infection of Escherichia coli B with T4 phage with DO amber mutation in gene 44, a minimal amount of phage DNA is synthesized. This progeny DNA is, for the most part, covalently attached to the parental DNA. Analysis of the genetic representation of this DNA was performed by hybridization to cloned genetic segments. It was shown that areas preferentially replicated differ from origins observed in "normal" replication: under normal conditions, there is a strong origin in the genetic area of genes 50-5 and lack of initiation within the group of genes 40-43 and 35-52. In contrast, in the absence of the gene 44 protein, the genetic area of 50-5 is underrepresented, genes 35-36, tRNA, and genes 40-41 are the most prominent among progeny DNA, and the area of gene 39 is least represented. Since the area of gene 35 is known from the genetic data or other to be a high-frequency recombination area, and since the area of gene 39 is known to display a low frequency of recombination, we postulate that the observed uptake of label occurs at the site-specific recombinational intersections.