Bacteriophage T7/Overview

The following is rewritten based on Chan, Kosuri and Endy, 2005 Chan.

Bacteriophage T7, an obligate lytic phage that infects Escherichia coli (Dunn and Studier, 1983; Studier and Dunn, 1983), offers an attractive model system for genome design and engineering for several reasons.

• Genetics, and then biochemistry, enabled the discovery and characterization of some of the individual elements that participate in T7 development (Molineux, 2005).
• Compared to other phage, T7 is relatively independent of complex host physiology. For example, the optical density of T7-infected cultures stops increasing at the time of infection. T7 encodes phage-specific RNA and DNA polymerases, and E. coli mRNA and protein synthesis is inhibited within the first 6 min of T7 infection.
• RNA polymerase pulls most of the T7 genome into the newly infected cell (Zavriev and Shemyakin, 1982; Garcia and Molineux, 1995). Polymerase-mediated genome entry is a relatively slow process that results in the direct physical coupling of gene expression dynamics to gene position. For example, a gene cannot be expressed until its coding domain enters the newly infected cell.