Meeting Abstract
The genomic era has revealed that metazoan body plan diversification may rely on the selected expansion and diversification of transcription factor families as well as the developmental gene regulatory circuits these proteins regulate. Shifting dimerization activity within transcription factor superfamilies is one potent strategy for changing regulatory network attributes. Understanding changes in the protein-protein interactions of developmental transcription factors is crucial for uncovering the mechanisms of animal development, disease progression and other transcription factor-mediated processes. To probe the evolution of transcription factor protein-protein interactions in the metazoan lineage, we focused on the bZIP superfamily of transcription factors. bZIP proteins are highly conserved, dimer-forming eukaryotic transcription factors that regulate a variety of central cellular and tissue-grade functions. bZIPs act both as environmental biosensors and as intrinsic regulators of body plan. The central role of bZIPs in development led us to ask whether the complexity of bZIP interactions encoded by a genome increases as organisms become more complex. In this study, we used data-driven predictive algorithms to predict the entire bZIP “interactome” of 18 species that span the metazoan lineage and closely related unicellular outgroups. Our results show that a general increase in bZIP dimerization complexity accompanies the transition from unicellular outgroups to the multicellular animals. We also show that bZIP promiscuity is surprisingly high in the cnidarian lineage, surpassing dimerization complexity contained in all representatives of Bilateria excluding vertebrates. This study indicates, with high representative species resolution, that increases in bZIP dimerization activity are decoupled from an increase in morphological complexity.
