Title

Single-molecule fluorescence microscopy reveals modulation of DNA polymerase IV-binding lifetimes by UmuD (K97A) and UmuD′

Publication Name

Current Genetics

Abstract

DNA polymerase IV (pol IV) is expressed at increased levels in Escherichia coli cells that suffer DNA damage. In a recent live-cell single-molecule fluorescence microscopy study, we demonstrated that the formation of pol IV foci is strongly recB-dependent in cells treated with the DNA break-inducing antibiotic ciprofloxacin. The results of that study support a model in which pol IV acts to extend D-loop structures during recombinational repair of DNA double-strand breaks. In the present study, we extend upon this work, investigating the UmuD and UmuDʹ proteins as potential modulators of pol IV activity in ciprofloxacin-treated cells. We found that the non-cleavable mutant UmuD(K97A) promotes long-lived association of pol IV with the nucleoid, whereas its cleaved form, UmuDʹ, which accumulates in DNA-damaged cells, reduces binding. The results provide additional support for a model in which UmuD and UmuDʹ directly modulate pol IV-binding to the nucleoid.

Open Access Status

This publication is not available as open access

Funding Number

APP1165135

Funding Sponsor

Australian Research Council

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Link to publisher version (DOI)

http://dx.doi.org/10.1007/s00294-020-01134-3