Single-stranded DNA transposition is coupled to host replication.
DNA transposition has contributed significantly to evolution of eukaryotes and prokaryotes. Insertion sequences (ISs) are the simplest prokaryotic transposons and are divided into families on the basis of their organization and transposition mechanism. Here, we describe a link between transposition of IS608 and ISDra2, both members of the IS200/IS605 family, which uses obligatory single-stranded DNA intermediates, and the host replication fork. Replication direction through the IS plays a crucial role in excision: activity is maximal when the "top" IS strand is located on the lagging-strand template. Excision is stimulated upon transient inactivation of replicative helicase function or inhibition of Okazaki fragment synthesis. IS608 insertions also exhibit an orientation preference for the lagging-strand template and insertion can be specifically directed to stalled replication forks. An in silico genomic approach provides evidence that dissemination of other IS200/IS605 family members is also linked to host replication.
Ton-Hoang
Bao
B
Laboratoire de Microbiologie et Génétique Moléculaires, Centre National de Recherche Scientifique, Unité Mixte de Recherche 5100, 118 Route de Narbonne, F31062 Toulouse Cedex, France. bao.tonhoang@ibcg.biotoul.fr
Pasternak
Cécile
C
Siguier
Patricia
P
Guynet
Catherine
C
Hickman
Alison Burgess
AB
Dyda
Fred
F
Sommer
Suzanne
S
Chandler
Michael
M
D004265:DNA Helicases / Q000378:metabolism; D019915:DNA Primase / Q000378:metabolism; D004261:DNA Replication; D004251:DNA Transposable Elements; D004277:DNA, Single-Stranded / Q000378:metabolism*; D034301:Deinococcus / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism
D004251:DNA Transposable Elements; D004277:DNA, Single-Stranded; D029968:Escherichia coli Proteins; D015534:Trans-Activators; C045264:replication initiator protein; C489236:tus protein, E coli; D019915:DNA Primase; D004265:DNA Helicases