page_title: Gene transfer agent
section_title: GTA-mediated transduction
hierarchical_section_title: Gene transfer agent / GTA-mediated transduction
caption_attribution_description: English: Schematic diagram of genetic transduction by bacterial Gene Transfer Agents
context_page_description: Gene transfer agents are DNA-containing virus-like particles that are produced by some bacteria and archaea and mediate horizontal gene transfer. Different GTA types have originated independently from viruses in several bacterial and archaeal lineages. These cells produce GTA particles containing short segments of the DNA present in the cell. After the particles are released from the producer cell, they can attach to related cells and inject their DNA into the cytoplasm. The DNA can then become part of the recipient cells' genome.
context_section_description: Whether release of GTA particles leads to transfer of DNA to new genomes depends on several factors.   First, the particles must survive in the environment – little is known about this, although particles are reported to be quite unstable under laboratory conditions. Second, particles must encounter and attach to suitable recipient cells, usually members of the same or a closely related species.  Like phages, GTAs attach to specific protein or carbohydrate structures on the recipient cell surface before injecting their DNA.  Unlike phage, the well-studied GTAs appear to inject their DNA only across the first of the two membranes surrounding the recipient cytoplasm, and they use a different system, competence-derived rather than phage-derived, to transport one strand of the double-stranded DNA across the inner membrane into the cytoplasm.
  If the cell's recombinational repair machinery finds a chromosomal sequence very similar to the incoming DNA, it replaces the former with the latter by homologous recombination, mediated by the cell's RecA protein. If the sequences are not identical this will produce a cell with a new genetic combination.  However, if the incoming DNA is not closely related to DNA sequences in the cell it will be degraded, and the cell will reuse its nucleotides for DNA replication.
caption: Genetic transduction by bacterial gene transfer agents. (1) GTA particles encounter a suitable recipient cell.  (2) Particles attach to cell and inject their DNA, and cellular proteins translocate the DNA across the inner membrane. (3) DNA is degraded if it cannot recombine with the recipient genome. (4) DNA with similar sequences to the recipient genome undergoes recombination.
exif: {}