The joining of blunt DNA ends to 3'-protruding single strands in Escherichia coli.
In eukaryotic and prokaryotic organisms DNA double-strand breaks with non-complementary ends can be joined by mechanisms of illegitimate recombination. We examined the joining of 3'-protruding single strand (PSS) ends, which do not have recessed 3' hydroxyls that can allow for fill-in DNA synthesis, to blunt ends. End-joining was examined by electro-transforming Escherichia coli strains with linearized plasmid DNA, sequencing the resulting junctions, and determining the transformation frequencies. Three different E.coli strains were examined: MC1061, which has no known recombination or DNA repair defects, HB101 (rec A-) and SURE (recB- recJ-). No striking differences were found in either the spectrum of products observed or the efficiency of end-joining between these strains. As in vertebrate systems, the majority of the products were overlaps between directly repeated DNA sequences. 3'-PSS are frequently preserved in vertebrate systems, but they were not preserved in our experiments unless the transforming DNA was pretreated with a DNA polymerase.
King
J
J
Department of Radiation Oncology, University of California, San Francisco, San Francisco, CA 94143-0750, USA. jeffking@acaciabio.com
Fairley
C
C
Morgan
W
W
D001483:Base Sequence; D004249:DNA Damage; D004260:DNA Repair / Q000235:genetics*; D004262:DNA Restriction Enzymes / Q000378:metabolism*; D004269:DNA, Bacterial / Q000737:chemistry / Q000378:metabolism*; D004277:DNA, Single-Stranded / Q000737:chemistry / Q000378:metabolism*; D015257:DNA-Cytosine Methylases / Q000378:metabolism; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D005838:Genotype; D009838:Oligodeoxyribonucleotides / Q000737:chemistry / Q000378:metabolism; D011995:Recombination, Genetic / Q000235:genetics; D013379:Substrate Specificity
D004269:DNA, Bacterial; D004277:DNA, Single-Stranded; D009838:Oligodeoxyribonucleotides; C047084:DNA modification methylase PvuII; D015257:DNA-Cytosine Methylases; D004259:DNA-Directed DNA Polymerase; D004262:DNA Restriction Enzymes; C046184:endodeoxyribonuclease PaeI; D015252:Deoxyribonucleases, Type II Site-Specific; C069035:GACGTC-specific type II deoxyribonucleases