Regulation of cell fate determination by single-repeat R3 MYB transcription factors in Arabidopsis.

Shucai Wang,Jin-Gui Chen

doi:10.3389/fpls.2014.00133

Abstract

MYB transcription factors regulate multiple aspects of plant growth and development. Among the large family of MYB transcription factors, single-repeat R3 MYBs are characterized by their short sequence (<120 amino acids) consisting largely of the single MYB DNA-binding repeat. In the model plant Arabidopsis, R3 MYBs mediate lateral inhibition during epidermal patterning and are best characterized for their regulatory roles in trichome and root hair development. R3 MYBs act as negative regulators for trichome formation but as positive regulators for root hair development. In this article, we provide a comprehensive review on the role of R3 MYBs in the regulation of cell type specification in the model plant Arabidopsis.

Highlights

In plants, MYB transcription factors are encoded by a large family of genes (Stracke et al, 2001; Chen et al, 2006; Dubos et al, 2010; Katiyar et al, 2012)
Genetic and molecular studies suggested that R3 MYB transcription factors (R3 MYBs) move from a trichome precursor cell to its neighboring cell to compete with GL1 for binding GL3 or ENHANCER OF GLABRA3 (EGL3), limiting the activity of the TESTA GLABRA1 (TTG1)-GL3/EGL3-GL1 activator complex and resulting in decreased expression of GL2; this results in the inhibition of trichome formation (Figure 3)
The expression of TRY, CPC, ENHANCER OF TRY AND CPC1 (ETC1), and ENHANCER OF TRY AND CPC3 (ETC3) were found to be regulated by the TTG1-GL3/EGL3-GL3 activator complex

Summary

Introduction

MYB transcription factors are encoded by a large family of genes (Stracke et al, 2001; Chen et al, 2006; Dubos et al, 2010; Katiyar et al, 2012). The genetic control of root hair formation is remarkably similar to that of trichome initiation with all same components in the activator complex except that GL1 is replaced by another R2R3-MYB transcription factor, WEREWOLF (WER) (Lee and Schiefelbein, 1999). Triple and quadruple mutants revealed that other R3 MYB genes may function redundantly with CPC to positively regulate root hair formation.

Results

Conclusion