Replication at restrictive temperatures in Escherichia coli containing a polCts mutation.

Publisher Website
Google Scholar
Abstract
E. coli cells with a polCts mutation contain a temperature-sensitive DNA polymerase III and fail to replicate DNA at the restrictive temperature (43.degree. C). Mutants deficient in polymerizing activity of the other 2 recognized DNA polymerases in E. coli can replicate DNA. Temperature-resistant revertants from a strain containing polA-, polB- and polCts mutations were isolated. These revertants grow at 43.degree., but analysis of partially purified DNA polymerase III from several such revertants shows a temperature-sensitive DNA polymerase III activity. Genetic analysis by [phage] P1 transduction confirms that such revertants can contain a polCts mutation and also a polA- mutation. Such revertants behave phenotypically as PolI+ cells (DNA polymerase I-containing), and extracts of such cells show a DNA polymerase I-like activity. Revertants of polA-, dnaAts and polA-, dnaBts strains do not show such a DNA polymerase activity.