Analysis of the DNA-Binding Activities of the Arabidopsis R2R3-MYB Transcription Factor Family by One-Hybrid Experiments in Yeast

Abstract

The control of growth and development of all living organisms is a complex and dynamic process that requires the harmonious expression of numerous genes. Gene expression is mainly controlled by the activity of sequence-specific DNA binding proteins called transcription factors (TFs). Amongst the various classes of eukaryotic TFs, the MYB superfamily is one of the largest and most diverse, and it has considerably expanded in the plant kingdom. R2R3-MYBs have been extensively studied over the last 15 years. However, DNA-binding specificity has been characterized for only a small subset of these proteins. Therefore, one of the remaining challenges is the exhaustive characterization of the DNA-binding specificity of all R2R3-MYB proteins. In this study, we have developed a library of Arabidopsis thaliana R2R3-MYB open reading frames, whose DNA-binding activities were assayed in vivo (yeast one-hybrid experiments) with a pool of selected cis-regulatory elements. Altogether 1904 interactions were assayed leading to the discovery of specific patterns of interactions between the various R2R3-MYB subgroups and their DNA target sequences and to the identification of key features that govern these interactions. The present work provides a comprehensive in vivo analysis of R2R3-MYB binding activities that should help in predicting new DNA motifs and identifying new putative target genes for each member of this very large family of TFs. In a broader perspective, the generated data will help to better understand how TF interact with their target DNA sequences.

A Molecular Blueprint of Lignin Repression

“…Some members of the R2R3-MYB TF family positively regulate gene expression of phenylpropanoid and lignin biosynthetic genes containing AC-rich cis-elements in their promoters [30], such as the 7 bp sequence ACC(A/T)A(A/C)(T/C), termed the secondary wall MYB-responsive element (SMRE) [31,32]. The importance of MYBs as repressors of phenylpropanoid metabolism has been highlighted in a recent review [33].…”

The R2R3 MYB transcription factor PavMYB10.1 involves in anthocyanin biosynthesis and determines fruit skin colour in sweet cherry (Prunus aviumL.)

“…There were 10 amino acid residue differences in R2R3 domain between PavMYB10.1 and PavMYB10.2. Key amino acid residues of R2R3 domain may play an important role in the transcriptional control of biosynthesis (Heppel et al, 2013;Kelemen et al, 2015;Zimmermann et al, 2004). In the R2 domain, PavMYB10.1 contained an Arg at key position 40, while this residue was Lys in the PavMYB10.2.…”

Identification of novel MYB transcription factors involved in the isoflavone biosynthetic pathway by using the combination screening system with agroinfiltration and hairy root transformation

“…This program predicted three type1 MYBCORE elements (CNGTTR) located in the −388 bp, −453 bp, and −1005 bp regions of the GmCHS8 promoter (1662 bp), four MYBCORE elements located in the −387 bp, −1328 bp, −1354 bp, and −1567 bp regions of the GmIFS1 promoter (1740 bp), and a single MYBCORE element located in the −1245 bp region of the GmIFS2 promoter (1547 bp). MYBCORE elements consist of two sub-groups (type1 and type2); in a previous report, Arabidopsis R2R3-MYBs were shown to display high binding affinity to the type1 MYBCORE elements in a yeast one-hybrid system (Kelemen et al 2015). Therefore, type1 MYBCORE elements could be involved in the coordinate expression of GmCHS8, GmIFS1, and GmIFS2 genes via specific MYB TFs in soybean.…”