Open AccessF factor conjugation is a true type IV secretion system
Author(s) -
Lawley T.D,
Klimke W.A,
Gubbins M.J,
Frost L.S
Publication year - 2003
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1016/s0378-1097(03)00430-0
Subject(s) - bacterial conjugation , pilus , plasmid , secretion , gene , escherichia coli , pilin , biology , genetics , chemistry , biochemistry
The F sex factor of Escherichia coli is a paradigm for bacterial conjugation and its transfer ( tra ) region represents a subset of the type IV secretion system (T4SS) family. The F tra region encodes eight of the 10 highly conserved (core) gene products of T4SS including TraA F (pilin), the TraB F , ‐K F (secretin‐like), ‐V F (lipoprotein) and TraC F (NTPase), ‐E F , ‐L F and TraG F (N‐terminal region) which correspond to TrbC P , ‐I P , ‐G P , ‐H P , ‐E P , ‐J P , D P and TrbL P , respectively, of the P‐type T4SS exemplified by the IncP plasmid RP4. F lacks homologs of TrbB P (NTPase) and TrbF P but contains a cluster of genes encoding proteins essential for F conjugation (TraF F , ‐H F , ‐U F , ‐W F , the C‐terminal region of TraG F , and TrbC F ) that are hallmarks of F‐like T4SS. These extra genes have been implicated in phenotypes that are characteristic of F‐like systems including pilus retraction and mating pair stabilization. F‐like T4SS systems have been found on many conjugative plasmids and in genetic islands on bacterial chromosomes. Although few systems have been studied in detail, F‐like T4SS appear to be involved in the transfer of DNA only whereas P‐ and I‐type systems appear to transport protein or nucleoprotein complexes. This review examines the similarities and differences among the T4SS, especially F‐ and P‐like systems, and summarizes the properties of the F transfer region gene products.