EAR motif-mediated transcriptional repression in plants

Abstract

Ethylene-responsive element binding factor-associated Amphiphilic Repression (EAR) motif-mediated transcriptional repression is emerging as one of the principal mechanisms of plant gene regulation. The EAR motif, defined by the consensus sequence patterns of either LxLxL or DLNxxP, is the most predominant form of transcriptional repression motif so far identified in plants. Additionally, this active repression motif is highly conserved in transcriptional regulators known to function as negative regulators in a broad range of developmental and physiological processes across evolutionarily diverse plant species. Recent discoveries of co-repressors interacting with EAR motifs, such as TOPLESS (TPL) and AtSAP18, have begun to unravel the mechanisms of EAR motif-mediated repression. The demonstration of genetic interaction between mutants of TPL and AtHDA19, co-complex formation between TPL-related 1 (TPR1) and AtHDA19, as well as direct physical interaction between AtSAP18 and AtHDA19 support a model where EAR repressors, via recruitment of chromatin remodeling factors, facilitate epigenetic regulation of gene expression. Here, we discuss the biological significance of EAR-mediated gene regulation in the broader context of plant biology and present literature evidence in support of a model for EAR motif-mediated repression via the recruitment and action of chromatin modifiers. Additionally, we discuss the possible influences of phosphorylation and ubiquitination on the function and turnover of EAR repressors.

Functional analysis and binding affinity of tomato ethylene response factors provide insight on the molecular bases of plant differential responses to ethylene

“…To discriminate between the situation where the absence of activity is due to the lack of binding to the target promoter from those where the ERF binds but remains neutral on the promoter activity, we used chimerical constructs as effectors consisting of ERF coding sequences fused to the SRDX repressor motif [45]. Since the dominant repression activity of the chimerical construct is mediated by epigenetics mechanisms [46], the absence of repression with any of the ERF-SRDX constructs can be interpreted as resulting from the incapacity of the ERF to recognise the target promoter. Figure 3A shows that ERF proteins can not only act as activators or repressors, but can also be neutral on the ethylene-responsive promoters.…”

SlERF36, an EAR-motif-containing ERF gene from tomato, alters stomatal density and modulates photosynthesis and growth

“…These family members possess a C terminal motif L/FDLNL/FxP designated as the ERF-associated Amphiphilic Repression (EAR) motif that has been shown to be involved in repression not only in association with the AP2 domain but also in other transcription factors, such as C2H2 zinc finger proteins and AUX/IAA proteins, that lack the AP2 domain (Kagale et al , 2010; Kagale and Rozwadowski, 2011). In combination with the AP2 domain, there are eight members each of the EAR motif containing genes in Arabidopsis and rice (Nakano et al , 2006) and at least seven in tomato (Sharma et al , 2010).…”

Divergent Expression Patterns in Two Vernicia Species Revealed the Potential Role of the Hub Gene VmAP2/ERF036 in Resistance to Fusarium oxysporum in Vernicia montana

“…A previous report has suggested that transcription factors carrying this EAR motif form a complex with co-repressors and histone deacetylases (HDAs), favoring a closed chromatin structure to repress transcription [56]. Motif 15, containing the SP(T/V)SVL sequence, is found in group VI.…”