The role of supercoiling in mycobacteriophage L5 integrative recombination.
The genome of temperate mycobacteriophage L5 integrates into the chromosomes of its hosts, including Mycobacterium smegmatis , Mycobacterium tuberculosis and bacille Calmette-Guérin. This integrase-mediated site-specific recombination reaction occurs between the phage attP site and the mycobacterial attB site and requires the mycobacterial integration host factor. Here we examine the role of supercoiling in this reaction and show that integration is stimulated by DNA supercoiling but that supercoiling of either the attP or the attB substrate enhances recombination. Supercoiling thus facilitates a post-synaptic recombination event. We also show that, while supercoiling is not required for the production of a recombinagenic intasome, a mutant attP DNA deficient in binding of the host factor acquires a dependence on supercoiling for intasome formation and recombination.
Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA.
C E
CE
Peña
J M
JM
Kahlenberg
G F
GF
Hatfull
D001426:Bacterial Proteins / Q000378:metabolism; D010582:Bacteriophage lambda / Q000235:genetics; D001483:Base Sequence; D004264:DNA Topoisomerases, Type I / Q000378:metabolism; D004278:DNA, Superhelical / Q000235:genetics* / Q000378:metabolism; D004279:DNA, Viral / Q000235:genetics* / Q000378:metabolism; D034982:Integration Host Factors; D008969:Molecular Sequence Data; D009160:Mycobacteriophages / Q000235:genetics*; D009690:Nucleic Acid Conformation; D011995:Recombination, Genetic; D016662:Virus Integration / Q000235:genetics*
D001426:Bacterial Proteins; D004278:DNA, Superhelical; D004279:DNA, Viral; D034982:Integration Host Factors; D004264:DNA Topoisomerases, Type I