The auxin signalling network translates dynamic input into robust patterning at the shoot apex

Abstract

We provide a comprehensive expression map of the different genes (TIR1/AFBs, ARFs and Aux/IAAs) involved in the signalling pathway regulating gene transcription in response to auxin in the shoot apical meristem (SAM).We demonstrate a relatively simple structure of this pathway using a high-throughput yeast two-hybrid approach to obtain the Aux/IAA-ARF full interactome.The topology of the signalling network was used to construct a model for auxin signalling and to predict a role for the spatial regulation of auxin signalling in patterning of the SAM.We used a new sensor to monitor the input in the auxin signalling pathway and to confirm the model prediction, thus demonstrating that auxin signalling is essential to create robust patterns at the SAM.

Auxin-Induced Modulation of ETTIN Activity Orchestrates Gene Expression in Arabidopsis

“…Recognition of otherwise weak binding sites by ETT may be assisted by interaction with specific partners, which might be predominantly TFs given the interaction preferences exhibited by ETT in yeast two-hybrid library screenings (Simonini et al, 2016) and in interactome analyses (Vernoux et al, 2011). In accordance with ETT lacking the PB1 domain, interaction of ETT with AUX/IAA repressors has never been observed (Simonini et al, 2016;Vernoux et al, 2011).…”

“…Auxins comprise a class of plant hormones including the predominant auxin, indole-3-acetic acid (IAA), which is involved in an exceptional range of developmental processes during organ growth and differentiation (Benjamins and Scheres, 2008;Vanneste and Friml, 2009). In the nucleus, high auxin levels cause degradation of the Aux/IAA repressors, allowing auxin response factors (ARFs) to regulate transcription of their target genes in a signaling cascade that culminates in a myriad of different pathways (Vernoux et al, 2011;Rademacher et al, 2012;Calderón-Villalobos et al, 2012;Weijers and Wagner, 2016). The Arabidopsis thaliana genome encodes 23 ARFs and the N-terminal region of each ARF possesses a conserved DNA binding domain (DBD) able to mediate ARF dimerization and recognize auxin response elements (AuxREs) with the general sequence motif TGTCNN.…”

Auxin-Binding Protein 1 is a negative regulator of the SCFTIR1/AFB pathway

“…An attractive hypothesis is that the ABP1 pathway would confer auxin conditionality to the interaction between TIR1/AFBs and AUX/IAAs. Such conditionality might result from a change in subcellular or nuclei protein localization of AUX/IAA and/or TIR1/AFB proteins 22,33 , from the presence or absence of another protein or peptide interacting or competing with one of the component of the transcriptional regulatory module [34][35][36][37] or from post-translational modification affecting the relative affinity between TIR1/AFBs 38 and AUX/ IAAs 28,39 . A future challenge will be to elucidate the molecular basis of the action of ABP1 on the SCF TIR1/AFB pathway and to identify ABP1 downstream signalling elements filling the gap between ABP1 and the nuclear-localized SCF TIR1/AFB pathway.…”

Genome-wide inference of protein interaction network and its application to the study of crosstalk in Arabidopsis abscisic acid signaling

“…Compared with the performance of the other three methods, AraPPINet showed high predictive power for discovering interactions between protein family members with a mean TPR of 69.5%. In addition, interactions between members of three specific transcription factor families identified by high-throughput experiments were used to evaluate the performance of AraPPINet for individual cases, including 255 interactions among 72 MADS, 25 interactions among 17 bZIP, and 418 interactions among 49 ARF/IAA transcription factors (de Folter et al, 2005;Ehlert et al, 2006;Vernoux et al, 2011). As shown in Figure 2B, AraPPINet had AUC values ranging from 0.65 for the MADS family to 0.77 for the bZIP family.…”