Organspezifische DNA-Bindung und Transkriptionsregulation durch floral homöotische Transkriptionsfaktoren
Zusammenfassung der Projektergebnisse
Flower development is a complex biological process that is controlled by a dynamic gene regulatory network. Within this network, MADS-box transcription factors (TFs) play a significant role in coordinating gene expression. They are considered to be the master regulators of many developmental processes, particularly flower development. Despite being a well-conserved protein family, each member has specific functions that are critical for flower organ specification. The mechanism by which MADS-domain TFs achieve their functional specificity is still unknown. In the first phase of this project, we investigated the contribution of the M, I, K, and C protein domains of MADS-domain TFs to their functional specificity. We used a series of chimera proteins that combined the AGAMOUS (AG) and APETALA 1 (AP1) MADS- domain TFs domains. In vitro assays showed that the M domain is sufficient to confer DNA-binding specificity, while extensive in vivo phenotypic analysis indicated that the M and I domains played a major role in AP1 functional specificity in the AG context. MADS-box TFs have a crucial role in controlling a diverse set of target genes. However, the precise mechanisms by which these factors activate or repress transcription are still being explored. Emerging evidence suggests that co-regulators, including LEUNIG (LUG), LEUNIG HOMOLOG (LUH), and SEUSS (SEU), may be integral to the regulatory machinery of MADS-domain TFs. In the second phase of this project, we focused on characterizing the regulatory activities of LUH during different stages of flower development, specifically in conjunction with MADS-domain TFs AP1 and SEP3. Through immunoprecipitation assays followed by mass spectrometry (IP-MS), we discovered that LUH interacts with a multitude of factors, with MADS-domain TFs playing a significant role in these interactions. Coimmunoprecipitation assays revealed that the N-terminal part of LUH alone is sufficient for its interaction with AP1 and SEP3. Additionally, chromatin immunoprecipitation followed by sequencing (ChIP-seq) experiments indicated that LUH is involved in multiple flower developmental programs and shares a substantial number of common binding sites (BSs) with various MADS-domain TFs, particularly AP1. These studies contribute to our understanding of how MADS-domain TFs govern the specification of floral organ identities. The integration of our findings suggests that the regulation of flower developmental processes by MADS-domain TFs may involve collaborative action with transcriptional co-factors. These findings open up promising avenues for further research on this subject.
Projektbezogene Publikationen (Auswahl)
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The intervening domain is required for DNA-binding and functional identity of plant MADS transcription factors. Nature Communications, 12(1).
Lai, Xuelei; Vega-Léon, Rosario; Hugouvieux, Veronique; Blanc-Mathieu, Romain; van der Wal, Froukje; Lucas, Jérémy; Silva, Catarina S.; Jourdain, Agnès; Muino, Jose M.; Nanao, Max H.; Immink, Richard; Kaufmann, Kerstin; Parcy, François; Smaczniak, Cezary & Zubieta, Chloe
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Immunoprecipitation-Mass Spectrometry (IP-MS) of Protein-Protein Interactions of Nuclear-Localized Plant Proteins. Methods in Molecular Biology, 163-181. Springer US.
Smaczniak, Cezary
