Abstract

The development of flowers is controlled by a gene regulatory network involving a cascade of transcription factors such as LEAFY (LFY) and MONOPTEROS (also called ARF5 ). Such transcription factors read and interpret the genomic information to drive the developmental progression and ensure the gene expression reprogramming needed for floral development. We use an integrated structural approach combining crystallography, genomics and modeling to understand how these transcription factors work, how they evolved and what roles they fulfill in plants.

I will present how we unraveled a new role for LFY in the emergence of stem cells by perturbing the dimerization of its DNA binding domain (DBD)1. We have also studied the evolution of this DBD : we found that LEAFY changed DNA binding specificity at least twice during evolution; we provide a structural explanation for these changes as well as a plausible smooth evolutionary pathway to explain how plants could tolerate that an essential factor evolved independently of duplications.

Finally, our structural approach also revealed that both LFY and ARF53 possess an oligomerization domain in addition to their dimeric DBD . We combined a biochemical approach, ChIP-seq experiments and the LFY DNA binding predictive model to show that oligomerization has a profound influence on LFY genomic DNA binding landscape4.

1: Chahtane et al. Plant Journal 2013

2: Sayou et al. Science 2014 and http://youtu.be/Yvk3ond-WHk

3: Nanao et al. Nature Commun. 2014