New research published in Science reveals how a critical plant transcription factor has undergone radical evolutionary change in DNA binding specificity. Combining high-throughout sequencing, crystallographic analysis and phylogenetic reconstruction, the authors show that the DNA binding mode of LEAFY, a central regulator of flower development, changed multiple times during evolution, via a promiscuous intermediate. This promiscuous LEAFY adopts a unique configuration on the DNA that allows it to bind several distinct DNA motifs, providing a smooth pathway between abrupt shifts in binding specificity. This work reveals a new mechanism for transcription factor evolution that can operate independently of gene duplication, but could also contribute to the evolution of transcription factors encoded by multi-gene families.
Edwige Moyroud from the Glover lab is a joint-first author on this study, initiated during her PhD in the Parcy lab in Grenoble (France). Samuel Brockington is also a co-author on the paper.
Link to the paper: doi 10.1126/science.1248229