Enhanced deletion formation by aberrant DNA replication in Escherichia coli.

摘要: Repeated genes and sequences are prone to genetic rearrangements including deletions. We have investigated deletion formation in Escherichia coli strains mutant for various replication functions. Deletion was selected between 787 base pair tandem repeats carried either on a ColE1-derived plasmid or the E. chromosome. Only mutations functions associated with DNA Polymerase III elevated rates our assays. Especially large increases were observed dnaQ ϵ editing subunit of Pol III, dnuB , fork helicase. Mutations several other also altered formation: α polymerase ( dnaE ), γ clamp loader complex holC, dnaX β dnaN ) subunits primosomal proteins, dnaC priA . Aberrant stimulated deletions through pathways. Whereas elevation dnaB mostly recA - lexA -dependent, that -independent. product analysis suggested slipped mispairing, producing monomeric replicon products, may be preferentially increased sister-strand exchange, dimeric mutants. conclude aberrant can stimulate events mechanisms via both -dependent independent