The Filamentous Phage Genome: Genes, Physical Structure, and Protein Products

Abstract

In this article we review the organization of the filamentous phage genome and the phage-specific protein products. A great deal of work has been done on the filamentous phages specific to strains of Escherichia coli carrying an F factor. Included in this category are f1 (Loeb 1960; Zinder et al. 1963), fd (Marvin and Hoffmann-Berling 1963), M13 (Hofschneider 1963), and ZJ/2 (Bradley 1964). These phages are so closely related that we will not usually distinguish among them. Other filamentous phages, including the I-specific phages of E. coli (Meynell and Lawn 1968) and the filamentous phages of Pseudomonas (Minamishima et al. 1968), have been described but are not included in this discussion.

We describe the properties of the various mutants of the filamentous phages, the organization of the genes on the genetic and physical maps, and the methylatable bases in the genome. We also list the gene products and describe some of their properties, as well as discuss aspects of the control of gene expression.

MUTANTS
Conditional Lethals
Initial genetic studies of the filamentous phages were carried out by Pratt and his colleagues (1966 colleagues (1969), who collected amber and temperature-sensitive mutants and classified them by standard complementation analysis into eight complementation groups. No additional genes have been identified since. In the Pratt collection, gene VIII is represented by only one conditionally lethal mutation, am8H1, and none of the other groups working with the filamentous phages have identified any other conditionally lethal mutations in gene VIII. Since the map is not saturated,...