TY - JOUR
T1 - Location of the unique integration site on an Escherichia coli chromosome by bacteriophage lambda DNA in vivo
AU - Tal, Asaf
AU - Arbel-Goren, Rinat
AU - Costantino, Nina
AU - Court, Donald L.
AU - Stavans, Joel
N1 - Yeda-Sela Center of the Weizmann Institute of Science; National Institutes of Health, National Cancer Institute, Center for Cancer ResearchWe thank S. Austin for comments and plasmids, L. Thomason for the gift of lambda strain cI857 bor::kan<SUP>R</SUP>, and O. Kobiler, and J. Sawitzke for a careful reading of the manuscript. This work was supported in part by the Yeda-Sela Center of the Weizmann Institute of Science (J. S.), and by the Intramural Research Program of the National Institutes of Health, National Cancer Institute, Center for Cancer Research (D.L.C.).
PY - 2014/5/20
Y1 - 2014/5/20
N2 - The search for specific sequences on long genomes is a key process in many biological contexts. How can specific target sequences be located with high efficiency, within physiologically relevant times? We addressed this question for viral integration, a fundamental mechanism of horizontal gene transfer driving prokaryotic evolution, using the infection of Escherichia coli bacteria with bacteriophage λ and following the establishment of a lysogenic state. Following the targeting process in individual live E. coli cells in real time revealed that λ DNA remains confined near the entry point of a cell following infection. The encounter between the 15-bp-long target sequence on the chromosome and the recombination site on the viral genome is facilitated by the directed motion of bacterial DNA generated during chromosome replication, in conjunction with constrained diffusion of phage DNA. Moving the native bacterial integration site to different locations on the genome and measuring the integration frequency in these strains reveals that the frequencies of the native site and a site symmetric to it relative to the origin are similar, whereas both are significantly higher than when the integration site is moved near the terminus, consistent with the replication-driven mechanism we propose. This novel search mechanism is yet another example of the exquisite coevolution of λ with its host.
AB - The search for specific sequences on long genomes is a key process in many biological contexts. How can specific target sequences be located with high efficiency, within physiologically relevant times? We addressed this question for viral integration, a fundamental mechanism of horizontal gene transfer driving prokaryotic evolution, using the infection of Escherichia coli bacteria with bacteriophage λ and following the establishment of a lysogenic state. Following the targeting process in individual live E. coli cells in real time revealed that λ DNA remains confined near the entry point of a cell following infection. The encounter between the 15-bp-long target sequence on the chromosome and the recombination site on the viral genome is facilitated by the directed motion of bacterial DNA generated during chromosome replication, in conjunction with constrained diffusion of phage DNA. Moving the native bacterial integration site to different locations on the genome and measuring the integration frequency in these strains reveals that the frequencies of the native site and a site symmetric to it relative to the origin are similar, whereas both are significantly higher than when the integration site is moved near the terminus, consistent with the replication-driven mechanism we propose. This novel search mechanism is yet another example of the exquisite coevolution of λ with its host.
UR - http://www.scopus.com/inward/record.url?scp=84901049718&partnerID=8YFLogxK
U2 - 10.1073/pnas.1324066111
DO - 10.1073/pnas.1324066111
M3 - مقالة
SN - 0027-8424
VL - 111
SP - 7308
EP - 7312
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 20
ER -