Mutual control of intracellular localisation of the patterning proteins AtMYC1, GL1 and TRY/CPC inArabidopsis

Abstract

SUMMARYTrichome and root hair patterning is governed by a gene regulatory network involving TTG1 and several homologous MYB and bHLH proteins. The bHLH proteins GL3 and EGL3 are core components that serve as a regulatory platform for the activation of downstream genes. In this study we show that a homologue of GL3 and EGL3, AtMYC1, can regulate the intracellular localisation of GL1 and TRY. AtMYC1 protein is predominantly localised in the cytoplasm and can relocate GL1 from the nucleus into the cytoplasm. Conversely, AtMYC1 can be recruited into the nucleus by TRY and CPC, concomitant with a strong accumulation of TRY and CPC in the nucleus. When AtMYC1 is targeted to the nucleus or cytoplasm by nuclear localisation or export signals (NLS or NES), respectively, the intracellular localisation of GL1 and TRY also changes accordingly. The biological significance of this intracellular localisation is suggested by the finding that the efficiency of rescue of trichome number is significantly altered in NES and NLS fusions as compared with wild-type AtMYC1. Genetic analysis of mutants and overexpression lines supports the hypothesis that AtMYC1 represses the activity of TRY and CPC.

TRANSPARENT TESTA GLABRA1 and GLABRA1 Compete for Binding to GLABRA3 in Arabidopsis

“…pcDNA3-Rluc-GW and pTREXdest30 (Invitrogen) enable the N-terminal fusion of Renilla reniformis and Staphylococcus aureus proteins, respectively, and were described before (Pesch et al, 2013). pTREX-dest30re enables unfused protein expression.…”

bHLH05 Is an Interaction Partner of MYB51 and a Novel Regulator of Glucosinolate Biosynthesis in Arabidopsis

“…Several studies that aimed to understand transcriptional gene regulation by the MYB-bHLH complex have addressed this in trichome patterning and the differentiation of epidermal cells (Glover et al, 1998;Bernhardt et al, 2005;Pesch and Hülskamp, 2009;Pesch et al, 2013) in Arabidopsis. Furthermore, the MYB-bHLH protein complexes involved in the regulation of flavonoid genes in Arabidopsis and also in other species such as rice (Oryza sativa), maize (Zea mays), cotton (Gossypium hirsutum), apple (Malus domestica), strawberry (Fragaria spp.…”

“…The coding sequences of MYB51 and bHLH05 were transferred from the entry clones into the gateway pCL112 YFP N-terminal and pCL113 YFP C-terminal vectors, respectively (kindly provided by Sean Chapman, SCRI, and recently described by Pesch et al, 2013). The nuclear-localized factor bHLH133, which was cloned into the pCL113 YFP C-terminal vector, was used as a negative control for the interaction with MYB51.…”

“…The LUMIER assay is based on the techniques of Barrios-Rodiles et al (2005) for mammalian proteins and Pesch et al (2013) for plant proteins. The LUMIER assay was performed as described by Pesch et al (2013), with slight modifications.…”

“…The LUMIER assay was performed as described by Pesch et al (2013), with slight modifications. To fuse luciferase from Renilla reniformis or protein A from Staphylococcus aureus to MYB and bHLH proteins, the two destination vectors pcDNA3-Rluc-GW and pTREX-dest30-ntPrA were recombined by LR reaction with the respective entry clones.…”