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Alexis Peaucelle

Publications and source records attributed to Alexis Peaucelle.

5 recordsLinked to original sources
PubMed2006

The balance between the MIR164A and CUC2 genes controls leaf margin serration in Arabidopsis.

CUP-SHAPED COTYLEDON1 (CUC1), CUC2, and CUC3 define the boundary domain around organs in the Arabidopsis thaliana meristem. CUC1 and CUC2 transcripts are targeted by a microRNA (miRNA), miR164, encoded by MIR164A, B, and C. We show that each MIR164 is transcribed to generate a large population of primary miRNAs of variable size with a locally conserved secondary structure around the pre-miRNA. We identified mutations in the MIR164A gene that deepen serration of the leaf margin. By contrast, leaves of plants overexpressing miR164 have smooth margins. Enhanced leaf serration was observed following the expression of an miR164-resistant CUC2 but not of an miR164-resistant CUC1. Furthermore, CUC2 inactivation abolished serration in mir164a mutants and the wild type, whereas CUC1 inactivation did not. Thus, CUC2 specifically controls leaf margin development. CUC2 and MIR164A are transcribed in overlapping domains at the margins of young leaf primordia, with transcription gradually restricted to the sinus, where the leaf margins become serrated. We suggest that leaf margin development is controlled by a two-step process in Arabidopsis. The pattern of serration is determined first, independently of CUC2 and miR164. The balance between coexpressed CUC2 and MIR164A then determines the extent of serration.

Alleles↗
PubMed2006

Cell differentiation and organ initiation at the shoot apical meristem.

Plants continuously generate organs at the flanks of their shoot apical meristems (SAMs). The patterns in which these organs are initiated, also called patterns of phyllotaxis, are highly stereotypic and characteristic for a particular species or developmental stage. This stable, predictable behaviour of the meristem has led to the idea that organ initiation must be based on simple and robust mechanisms. This conclusion is less evident, however, if we consider the very dynamic behaviour of the individual cells. How dynamic cellular events are coordinated and how they are linked to the regular patterns of organ initiation is a major issue in plant developmental biology.

Cell Differentiation↗
PubMed2004

MicroRNA regulation of the CUC genes is required for boundary size control in Arabidopsis meristems.

We have analysed the role of a microRNA, miR164, in boundary formation during organ initiation from Arabidopsis meristems. The establishment and maintenance of the boundary domain are controlled by three partially redundant genes, CUP-SHAPED COTYLEDON1 (CUC1), CUC2 and CUC3. We show that miR164 overexpression phenocopies the cuc1 cuc2 double mutant by inducing post-transcriptional downregulation of CUC1 and CUC2 but not CUC3 mRNA levels. Disruption of CUC2 regulation by miR164, either by making CUC2 resistant to the miRNA or by reducing miRNA levels leads to similar enlarged boundary domains. We relate this enlargement to the division patterns of the boundary cells. We propose that miR164 constrains the expansion of the boundary domain, by degrading CUC1 and CUC2 mRNAs.

Arabidopsis↗
PubMed2003

The ethanol switch: a tool for tissue-specific gene induction during plant development.

Controlled gene expression in time and space is a powerful tool for the analysis of gene function during plant development. Here, we report ethanol inducible gene expression in defined sub-domains of the shoot apical and floral meristems. For this, expression of an ethanol-regulated transcription factor, ALCR, is restricted to precise domains using specific promoters. Gene expression activation is followed using reporters under the control of the alcA promoter, which responds to ALCR only in the presence of the ethanol. We demonstrate that precise control of spatially limited gene expression can be achieved. The kinetics of reporter gene activation and inactivation following a pulse of ethanol induction shows that the system is dynamic and suitable for precise temporal control of expression. The system is both flexible and robust, permitting simultaneous expression of two genes in a given domain or, conversely, the expression of a gene in two separate domains. We also show that this strategy can be applied to mis-express genes with developmental roles, by manipulating expression of the SHOOT MERISTEMLESS (STM) and CYCLIN D3;1 (CYCD3;1) genes during plant development.

Arabidopsis↗