https://pmc.ncbi.nlm.nih.gov/articles/PMC50382/
SpCOUP-TF: a sea urchin member of the steroid/thyroid hormone receptor family - PMC
Embryonic nuclear proteins from the sea urchin Strongylocentrotus purpuratus bind in vitro to a cis-acting element that lies upstream of the actin gene CyIIIb...