Skip to main content
padlock icon - secure page this page is secure

Free Content Together yes, but not coupled: new insights into the roles of RAD51 and DMC1 in plant meiotic recombination

Download Article:

The eukaryotic recombinases RAD51 and DMC1 are essential for DNA strand‐exchange between homologous chromosomes during meiosis. RAD51 is also expressed during mitosis, and mediates homologous recombination (HR) between sister chromatids. It has been suggested that DMC1 might be involved in the switch from intersister chromatid recombination in somatic cells to interhomolog meiotic recombination. At meiosis, the Arabidopsis Atrad51 null mutant fails to synapse and has extensive chromosome fragmentation. The Atdmc1 null mutant is also asynaptic, but in this case chromosome fragmentation is absent. Thus in plants, AtDMC1 appears to be indispensable for interhomolog homologous recombination, whereas AtRAD51 seems to be more involved in intersister recombination. In this work, we have studied a new AtRAD51 knock‐down mutant, Atrad51‐2, which expresses only a small quantity of RAD51 protein. Atrad51‐2 mutant plants are sterile and hypersensitive to DNA double‐strand break induction, but their vegetative development is apparently normal. The meiotic phenotype of the mutant consists of partial synapsis, an elevated frequency of univalents, a low incidence of chromosome fragmentation and multivalent chromosome associations. Surprisingly, non‐homologous chromosomes are involved in 51% of bivalents. The depletion of AtDMC1 in the Atrad51‐2 background results in the loss of bivalents and in an increase of chromosome fragmentation. Our results suggest that a critical level of AtRAD51 is required to ensure the fidelity of HR during interchromosomal exchanges. Assuming the existence of asymmetrical DNA strand invasion during the initial steps of recombination, we have developed a working model in which the initial step of strand invasion is mediated by AtDMC1, with AtRAD51 required to check the fidelity of this process.
No References
No Citations
No Supplementary Data
No Article Media
No Metrics

Document Type: Research Article

Affiliations: 1: Departamento de Genética, Facultad de Biología, Universidad Complutense de Madrid, Madrid 28040, Spain 2: School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK

Publication date: March 1, 2012

  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more