AXL and AXR1 have redundant functions in RUB conjugation and growth and development in Arabidopsis.

N. Dharmasiri, S. Dharmasiri, D. Weijers, N. Karunaratha, G. Juergens, M. Estelle

Research output: Contribution to journalArticleAcademicpeer-review

52 Citations (Scopus)

Abstract

Cullin-RING ubiquitin-protein ligases such as the Skp1, cullin, F-box protein (SCF) have been implicated in many growth and developmental processes in plants. Normal SCF function requires that the CUL1 subunit be post-translationally modified by related to ubiquitin (RUB), a protein related to ubiquitin. This process is mediated by two enzymes: the RUB-activating and RUB-conjugating enzymes. In Arabidopsis, the RUB-activating enzyme is a heterodimer consisting of AXR1 and ECR1. Mutations in the AXR1 gene result in a pleiotropic phenotype that includes resistance to the plant hormone auxin. Here we report that the AXL (AXR1-like) gene also functions in the RUB conjugation pathway. Overexpression of AXL in the axr1-3 background complements the axr1-3 phenotype. Biochemical analysis indicates that AXL overexpression restores CUL1 modification to the wild-type level, indicating that AXR1 and AXL have the same biochemical activity. Although the axl mutant resembles wild-type plants, the majority of axr1 axl-1 double mutants are embryo or seedling lethal. Furthermore, the axl-1 mutation reveals novel RUB-dependent processes in embryo development. We conclude that AXR1 and AXL function redundantly in the RUB conjugating pathway.
Original languageEnglish
Pages (from-to)114-123
JournalThe Plant Journal
Volume52
Issue number1
DOIs
Publication statusPublished - 2007

Keywords

  • f-box protein
  • auxin response
  • ubiquitin-ligases
  • plant development
  • gene
  • encodes
  • thaliana
  • mutation
  • receptor
  • embryo

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