Fig. 6

The deep origin of novel cnidocyte-specific transcription factors in Cnidaria. This figure depicts the phylogenetic histories of (a) the c-Jun and b c-Fos family of proteins in Cnidaria. Duplication events leading to the origin of Cnido-Jun and Cnido-Fos1—the two cnidocyte-specific transcription factors identified in this study (labeled in red font)—and c-Jun and c-Fos (indicated in green font) in Hexacorallia are shown in red circles. Branches with node support ≥ 70 are shown in thick brown lines, and the bootstrap values for the major nodes are indicated. Domain organization of these proteins are also depicted, where the Jun-like domain, the bZIP domains, and the c-Fos-related domains are indicated in blue, green, and purple, respectively. The DNA binding domain is marked by black arrows, while the dimerization domains are depicted in red bars