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Spatially modelling WUSCHEL domain formation and robustness to CLAVATA3 promoter strength in the stem cell regulatory network of Arabidopsis

Korsbo, Niklas LU (2015) FYTM02 20142
Computational Biology and Biological Physics
Abstract (Swedish)
Clusters of stem cells at the tip of each plant shoot give rise to all of its above-ground organs, effectively controlling the development and the physical shape of the plant. A core network of negative feedback between CLAVATA3 (CLV3) and WUSCHEL (WUS) regulate the stem cells existence and behaviour in Arabidopsis thaliana. Despite the close relationship of these genes, their expression domains are kept spatially separated, and the network is found to be buffered to a ten-fold range of CLV3 promoter strength alterations.

This buffering ability and spatial regulation of WUS was investigated using an intimate combination of non-spatial and spatial computational modelling, in which non-spatially inferred parameter values were mapped to... (More)
Clusters of stem cells at the tip of each plant shoot give rise to all of its above-ground organs, effectively controlling the development and the physical shape of the plant. A core network of negative feedback between CLAVATA3 (CLV3) and WUSCHEL (WUS) regulate the stem cells existence and behaviour in Arabidopsis thaliana. Despite the close relationship of these genes, their expression domains are kept spatially separated, and the network is found to be buffered to a ten-fold range of CLV3 promoter strength alterations.

This buffering ability and spatial regulation of WUS was investigated using an intimate combination of non-spatial and spatial computational modelling, in which non-spatially inferred parameter values were mapped to spatial models. An incoherent feed forward motif, with the plant hormone cytokinin (CYT) diffusing quickly from the outer cell layer, was found able to place a gradient peak of CYT signal perception in the region of observed WUS expression. This, combined with a bistable signal processor of Arabidopsis response regulators, is shown to be able to initiate, maintain, and terminate a highly robust, homogeneous and sharp WUS domain. Two possible mechanisms of buffering were also identified. In one of them, a small change in WUS concentration can have a strong impact on CLV3, allowing it to compensate for perturbations to the CLV3 promoter, without itself changing notably. In the other, buffering was achieved by the saturation of receptors, effectively limiting the maximal perception of CLV3 in the WUS domain. (Less)
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@misc{7989302,
  abstract     = {Clusters of stem cells at the tip of each plant shoot give rise to all of its above-ground organs, effectively controlling the development and the physical shape of the plant. A core network of negative feedback between CLAVATA3 (CLV3) and WUSCHEL (WUS) regulate the stem cells existence and behaviour in Arabidopsis thaliana. Despite the close relationship of these genes, their expression domains are kept spatially separated, and the network is found to be buffered to a ten-fold range of CLV3 promoter strength alterations. 

This buffering ability and spatial regulation of WUS was investigated using an intimate combination of non-spatial and spatial computational modelling, in which non-spatially inferred parameter values were mapped to spatial models. An incoherent feed forward motif, with the plant hormone cytokinin (CYT) diffusing quickly from the outer cell layer, was found able to place a gradient peak of CYT signal perception in the region of observed WUS expression. This, combined with a bistable signal processor of Arabidopsis response regulators, is shown to be able to initiate, maintain, and terminate a highly robust, homogeneous and sharp WUS domain. Two possible mechanisms of buffering were also identified. In one of them, a small change in WUS concentration can have a strong impact on CLV3, allowing it to compensate for perturbations to the CLV3 promoter, without itself changing notably. In the other, buffering was achieved by the saturation of receptors, effectively limiting the maximal perception of CLV3 in the WUS domain.},
  author       = {Korsbo, Niklas},
  keyword      = {WUSCHEL,CLAVATA3,CLAVATA,CYTOKININ,ARR,ARABIDOPSIS RESPONCE REGULATOR,CORYNE,CRN,AHK4,ARABIDOPSIS HISTIDINE KINASE,L1,epidermis,Arabidopsis,Arabidopsis thaliana,multistability,bistability,fixed points,attractor,attractors,model,modelling,spatial,3D,buffering,domain,domain formation,incoherent feedback,incoherent feed forward},
  language     = {eng},
  note         = {Student Paper},
  title        = {Spatially modelling WUSCHEL domain formation and robustness to CLAVATA3 promoter strength in the stem cell regulatory network of Arabidopsis},
  year         = {2015},
}