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Translation factor IF2 at the interface of transposition and replication by the PriA‐PriC pathway
Author(s) -
North Stella H.,
Kirtland Sandy E.,
Nakai Hiroshi
Publication year - 2007
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2007.06022.x
Subject(s) - replisome , biology , dna replication , helicase , microbiology and biotechnology , eukaryotic translation , translation (biology) , initiation factor , dna , eukaryotic dna replication , genetics , gene , rna , messenger rna
Summary Bacteriophage Mu DNA synthesis is initiated during transposition by replication restart proteins PriA, DnaT and either PriB or PriC. The PriA‐PriC pathway requires PriA's helicase activity and other host factors that promote the orderly transition from transpososome to replisome on the Mu DNA template. The host factor MRFα‐PR, which removes obstacles to PriA binding and promotes the PriA‐PriC pathway, was identified to be the translation initiation factor IF2. Purified isoform IF2‐2, which is truncated at the N‐terminal end, had full MRFα‐PR activity whereas full‐length IF2‐1 was inactive. IF2‐2 was bound to the Mu DNA template specifically at the step for prereplisome assembly. Prior steps in the orderly transition from transpososome were essential to promote efficient IF2‐2 binding. Moreover, PriA helicase activity was subsequently needed to displace IF2‐2, remodelling the template to permit replisome assembly. IF2's role in the transition mechanism as well as its function as G protein and translation factor suggest its potential to regulate DNA synthesis by this pathway.