title: A subcellular tug of war involving three MYB-like proteins underlies a molecular antagonism in Antirrhinum flower asymmetry.
abstract: The establishment of meristematic domains with different transcriptional activity is essential for many developmental processes. The asymmetry of the Antirrhinum majus flower is established by transcription factors with an asymmetric pattern of activity. To understand how this asymmetrical pattern is established, we studied the molecular mechanism through which the dorsal MYB protein RADIALIS (RAD) restricts the activity of the MYB transcription factor DIVARICATA (DIV) to the ventral region of the flower meristem. We show that RAD competes with DIV for binding with other MYB-like proteins, termed DRIF1 and DRIF2 (DIV- and-RAD-interacting-factors). DRIF1 and DIV interact to form a protein complex that binds to the DIV-DNA consensus region, suggesting that the DRIFs act as co-regulators of DIV transcriptional activity. In the presence of RAD, the interaction between DRIF1 and DIV bound to DNA is disrupted. Moreover, the DRIFs are sequestered in the cytoplasm by RAD, thus, preventing or reducing the formation of DRIF-DIV heterodimers in the nuclei. Our results suggest that in the dorsal region of the Antirrhinum flower meristem the dorsal protein RAD antagonises the activity of the ventral identity protein DIV in a subcellular competition for a DRIF protein promoting the establishment of the asymmetric pattern of gene activity in the Antirrhinum flower.
authors: Center for Biodiversity Functional and Integrative Genomics (BioFIG), Plant Functional Biology Center, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal.
authors: João
authors: J
authors: Raimundo
authors: Rómulo
authors: R
authors: Sobral
authors: Paul
authors: P
authors: Bailey
authors: Herlânder
authors: H
authors: Azevedo
authors: Lisete
authors: L
authors: Galego
authors: Jorge
authors: J
authors: Almeida
authors: Enrico
authors: E
authors: Coen
authors: Maria Manuela R
authors: MM
authors: Costa
mesh_terms: D000595:Amino Acid Sequence; D032161:Antirrhinum / Q000166:cytology / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D035264:Flowers / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D018519:Meristem / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D010641:Phenotype; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D011994:Recombinant Proteins; D017422:Sequence Analysis, DNA; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D020798:Two-Hybrid System Techniques
chemical_list: D010940:Plant Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors
keywords: Antirrhinum majus; DIVARICATA; RADIALIS; dorsoventral asymmetry; molecular antagonism; myb-like proteins