Characterization of MADS-domain transcription factor complexes in Arabidopsis flower development.

Laboratory of Molecular Biology, Wageningen University, 6708PB Wageningen, The Netherlands.

Proceedings of the National Academy of Sciences of the United States of America 2012 Jan 31

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Floral organs are specified by the combinatorial action of MADS-domain transcription factors, yet the mechanisms by which MADS-domain proteins activate or repress the expression of their target genes and the nature of their cofactors are still largely unknown. Here, we show using affinity purification and mass spectrometry that five major floral homeotic MADS-domain proteins (AP1, AP3, PI, AG, and SEP3) interact in floral tissues as proposed in the "floral quartet" model. In vitro studies confirmed a flexible composition of MADS-domain protein complexes depending on relative protein concentrations and DNA sequence. In situ bimolecular fluorescent complementation assays demonstrate that MADS-domain proteins interact during meristematic stages of flower development. By applying a targeted proteomics approach we were able to establish a MADS-domain protein interactome that strongly supports a mechanistic link between MADS-domain proteins and chromatin remodeling factors. Furthermore, members of other transcription factor families were identified as interaction partners of floral MADS-domain proteins suggesting various specific combinatorial modes of action.

Citation

Cezary Smaczniak, Richard G H Immink, Jose M Muiño, Robert Blanvillain, Marco Busscher, Jacqueline Busscher-Lange, Q D Peter Dinh, Shujing Liu, Adrie H Westphal, Sjef Boeren, François Parcy, Lin Xu, Cristel C Carles, Gerco C Angenent, Kerstin Kaufmann. Characterization of MADS-domain transcription factor complexes in Arabidopsis flower development. Proceedings of the National Academy of Sciences of the United States of America. 2012 Jan 31;109(5):1560-5