Establishment and evolution of a gene regulatory network controlling flower asymmetry

Gene Regulatory Networks (GRN) dictate the patterns of expression in a cell. How changes in these networks lead to the emergence of phenotypic novelties is a major challenge in evolutionary developmental biology. The asymmetry of flowers constitutes a good model for studying the evolution of GRN, as this trait has emerged independently at least 25 times in the angiosperms. In Antirrhinum majus , the asymmetry of the flower depends on the regulation of a transcriptional module composed of three proteins: RADIALIS (RAD), DIVARICATA(DIV) and DIV-RAD-Interacting-Factors (DRIF). In the ventral part of the flower DIV interacts with DRIF to form a complex capable of binding DNA. On the dorsal part, RAD is expressed, and acts as a small interfering peptide binding to DRIF and preventing the formation of the DIV-DRIF complex. Our main purpose is to characterize the amino acids involved in protein-protein interactions between DIV-DRIF and DRIF-RAD. Based on sequence alignments and 3D model structure predictions, we will show the effect of mutagenized amino acid residues in the interaction between the different partners.