Gene transfer agent

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A gene transfer agent (GTA) is a bacteriophage-like element produced by several bacteria that mediates horizontal gene transfer. GTAs package random segments of DNA present in the host bacterium, which can be transduced to a recipient cell.

The model-GTA is the RcGTA produced by the alphaproteobacterium Rhodobacter capsulatus. When cultured in laboratory conditions, a subset of the bacterial population induces production of RcGTA upon entry into stationary phase, which are subsequently released from the cells through cell lysis.[1] Most of the RcGTA structural genes are encoded in a ~ 15 kb genetic cluster on the bacterial chromosome. However, other genes required for RcGTA function, such as the genes required for RcGTA release through cell lysis are located separately.[2][3] Production of RcGTA appears to be controlled by the host cell, because several host systems, including a quorum sensing system and a histidine kinase and response regulator [2] are required for RcGTA-transduction. Furthermore, the ability of cells to receive genetic material transduced by RcGTA requires a capsular polysaccharide receptor, which is regulated by the quorum sensing system.[4]

RcGTA-like clusters are found in several alphaproteobacteria.[5] Recently, several members of the order Rhodobacterales have been demonstrated to produce functional RcGTA-like particles.[6][7] In addition to the RcGTA-like GTAs, several other GTAs with no homology to RcGTA have been described. Of these, the best studied is VSH-1 produced by the spirochaete Brachyspira hyodysenteriae.[8]

See also[edit]


  1. ^ Fogg, P. C. M.; Westbye, A. B.; Beatty, J. T. (2012). Banfield, Bruce W, ed. "One for All or All for One: Heterogeneous Expression and Host Cell Lysis Are Key to Gene Transfer Agent Activity in Rhodobacter capsulatus". PLoS ONE. 7 (8): e43772. Bibcode:2012PLoSO...743772F. PMC 3423380Freely accessible. PMID 22916305. doi:10.1371/journal.pone.0043772. 
  2. ^ a b Lang, A. S.; Zhaxybayeva, O.; Beatty, J. T. (2012). "Gene transfer agents: Phage-like elements of genetic exchange". Nature Reviews Microbiology. 10: 472–82. PMC 3626599Freely accessible. PMID 22683880. doi:10.1038/nrmicro2802. 
  3. ^ Westbye, A. B.; Leung, M. M.; Florizone, S.; Taylor, T. A.; Johnson, J. A.; Fogg, P. C.; Beatty, J. T. (2013). "Phosphate concentration and the putative sensor-kinase protein CckA modulate cell lysis and release of the Rhodobacter capsulatus gene transfer agent (RcGTA)". Journal of Bacteriology. 195: 5025–40. PMC 3811591Freely accessible. PMID 23995641. doi:10.1128/JB.00669-13. 
  4. ^ Brimacombe, C. A.; Stevens, A.; Jun, D.; Mercer, R.; Lang, A. S.; Beatty, J. T. (2013). "Quorum-sensing regulation of a capsular polysaccharide receptor for theRhodobacter capsulatusgene transfer agent (RcGTA)". Molecular Microbiology. 87 (4): 802–817. PMC 3641046Freely accessible. PMID 23279213. doi:10.1111/mmi.12132. 
  5. ^ Lang, AS and Beatty, JT (2007) "Importance of widespread gene transfer agent genes in alpha-proteobacteria." Trends in Microbiology, 15(2) pp. 54–62. (Review)
  6. ^ McDaniel, L. D.; Young, E.; Delaney, J.; Ruhnau, F.; Ritchie, K. B.; Paul, J. H. (2010). "High Frequency of Horizontal Gene Transfer in the Oceans". Science. 330 (6000): 50. Bibcode:2010Sci...330...50M. PMID 20929803. doi:10.1126/science.1192243. 
  7. ^ Maxmen, A. (2010). "Virus-like particles speed bacterial evolution". Nature. doi:10.1038/news.2010.507. 
  8. ^ Stanton, TB (2007) "Prophage-like gene transfer agents-novel mechanisms of gene exchange for Methanococcus, Desulfovibrio, Brachyspira, and Rhodobacter species." Anaerobe, 13(2) pp. 43–49. (Review)