Field of Science

Experiments with stalled replication forks?

We think (I think) bacteria turn on their 'competence' genes because they are running out of deoxynucleotides for DNA synthesis. Part of this adaptive response is taking up DNA (an excellent dietary source of deoxynucleotides) and part of it is other changes that help cells cope with problems that arise when DNA replication is interrupted.

If I'm right, then cells with their competence genes already on might be better able to survive interruption of DNA replication. How can we test this? Are there antibiotics that block DNA replication, that can be used to create a transient block and then washed out? What about temperature-sensitive (ts) mutations in DNA replication genes? This might best be done in E. coli, not H. influenzae, because ts mutations don't work well in the latter ( it's intrinsically sensitive to minor shifts in temperature). E. coli also has a fine collection of already characterized ts mutations, and we now are able to artificially induce its CRP-S (competence) regulon by putting E. coli sxy on an inducible plasmid.

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