Chloé ZubietaLaboratoire de physiologie cellulaire et végétale (LPCV) - CNRS / CEA / UGA / INRA
Mes recherches
My scientific career has focused on understanding the atomic structure and molecular mechanisms underlying protein function. For my thesis studies, I focused on plant small molecule methyltransferases and their roles in secondary metabolism with Prof. Joseph Noel at the Salk Institute in La Jolla, California. With this basis in structural biology, biochemistry and enzymology, I tackled large viral protein complexes during my postdoctoral work with Dr. Stephen Cusack at the EMBL, Grenoble. I was recruited 6 years ago by the CNRS to apply these methods to the study of MADS transcription factors- key regulators of plant development, particularly floral organ morphogenesis. Concurrently with my recruitment, I applied for funding through the ATIP-Avenir program and started by own team in the Laboratoire de Physiologie Cellulaire et Végétale in Grenoble. My current research seeks to understand how transcription factors and transcription factor complexes regulate their target genes during major developmental transitions such as flowering and floral organ morphogenesis. This seemingly simple question requires the combination of in vitro structural and biophysical studies and in vivo genome-wide binding and transgenic experiments. The powerful synergy of these approaches allows my team to explore transcription factor function from the atomic to organismal level.
Mon projet ATIP-Avenir
My ATIP-Avenir project focused on a large family of transcription factors (TFs) called the MADS-domain TFs. These TFs have undergone extensive duplication and diversification in plants and constitute key TFs with roles in all aspects of plant reproduction including flower initiation, floral organ development, fruiting and seed set. From just a few MADS TFs in basal land plants to over 100 in higher flowering plants such as Arabidopsis, the evolution of the MADS TF family mirrors the evolution of land plants with increased plant complexity requiring an increase in the number of MADS TFs. Thus, the MADS-domain TF family is at the nexus of multiple developmental pathways in all higher plants. In order to both understand plant evolution and to tune crop plant reproduction for biotechnology applications, including improved fruit and seed yield, the molecular mechanisms of MADS TF function must be investigated. The ATIP-Avenir project addresses the fundamental question of how the MADS-domain TFs select and correctly regulate their target genes using an integrated approach. We study the atomic structure of the TFs alone and in complex with protein partners and DNA. In addition we perform genome-wide binding studies using techniques such as DNA-affinity purification followed by deep sequencing (DAP-seq) to better understand binding specificity of different MADS complexes. Using this combined approach we have revealed how the different MADS complexes are able to achieve binding specificity and correct target gene regulation. In addition, these techniques are broadly applicable and constitute an experimental blueprint for the study of diverse TFs and TF families in any organism.