Control of seed and organ size by a ubiquitin-mediated signalling cascade

Lead Research Organisation: John Innes Centre
Department Name: Contracts Office

Abstract

We have identified a novel ubiquitin-mediated signaling cascade involving the activation of DA1 peptidase by the E3 ligases EOD1/BB and DA2. DA1 then cleaves the E3 ligases and increases their activity in reducing the duration of cell proliferation during organ formation. Mutations in both DA1 and either E3 ligase lead to prolonged duration of cell proliferation during organ and seed formation, leading to larger organs and seeds. This has created exciting new opportunities for understanding mechanisms integrating cell proliferation with organogenesis, and for exploiting these discoveries to increase crop yields. The objectives of this research project are to:
1. Screen for additional substrates of DA1 peptidase activity. This will identify targets of the DA1-mediated ubiquitin signaling cascade and provide new insights into growth control and how it is orchestrated;
2. Conduct proteomic assays to identify substrates of the E3 ligases EOD1/BB and DA2. This will identify a wider range of downstream targets of the DA1-mediated ubiquitin signaling cascade;
3. Define how ubiquitination of DA1 by EOD1/BB regulates its peptidase activity and the timing and distribution of DA1 peptidase activity during organ formation. This is important for understanding how its cleavage of target proteins is coordinated during organ formation;
4. Understand the roles of DA1 targets, and EOD1/BB and DA2 substrates, in maintaining the balance of cell proliferation and cell differentiation during organ and seed formation.

Publications

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