Duplication and divergence: New insights into AXR1 and AXL functions in DNA repair and meiosis

Sci Rep. 2020 Jun 1;10(1):8860. doi: 10.1038/s41598-020-65734-2.

Abstract

Rubylation is a conserved regulatory pathway similar to ubiquitination and essential in the response to the plant hormone auxin. In Arabidopsis thaliana, AUXIN RESISTANT1 (AXR1) functions as the E1-ligase in the rubylation pathway. The gene AXR1-LIKE (AXL), generated by a relatively recent duplication event, can partially replace AXR1 in this pathway. We have analysed mutants deficient for both proteins and complementation lines (with the AXR1 promoter and either AXR1 or AXL coding sequences) to further study the extent of functional redundancy between both genes regarding two processes: meiosis and DNA repair. Here we report that whereas AXR1 is essential to ensure the obligatory chiasma, AXL seems to be dispensable during meiosis, although its absence slightly alters chiasma distribution. In addition, expression of key DNA repair and meiotic genes is altered when either AXR1 or AXL are absent. Furthermore, our results support a significant role for both genes in DNA repair that was not previously described. These findings highlight that AXR1 and AXL show a functional divergence in relation to their involvement in homologous recombination, exemplifying a duplicate retention model in which one copy tends to have more sub-functions than its paralog.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Axl Receptor Tyrosine Kinase
  • DNA Damage / radiation effects
  • DNA Repair*
  • Gamma Rays
  • Gene Expression Regulation, Plant
  • Homologous Recombination
  • Indoleacetic Acids / metabolism
  • Meiosis*
  • Plants, Genetically Modified / genetics
  • Plants, Genetically Modified / metabolism
  • Promoter Regions, Genetic
  • Proto-Oncogene Proteins / deficiency
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism*
  • Receptor Protein-Tyrosine Kinases / deficiency
  • Receptor Protein-Tyrosine Kinases / genetics
  • Receptor Protein-Tyrosine Kinases / metabolism*
  • Ubiquitination

Substances

  • AXR1 protein, Arabidopsis
  • Arabidopsis Proteins
  • Indoleacetic Acids
  • Proto-Oncogene Proteins
  • Receptor Protein-Tyrosine Kinases
  • Axl Receptor Tyrosine Kinase