- Günl M, Liew E, David K, Putterill J. Analysis of a post-translational steroid induction system for GIGANTEA in Arabidopsis. BMC Plant Biol. 2009;9:141 pubmed publisher..Known downstream flowering time genes CO and FT were elevated by DEX treatment, but not other proposed targets HAP3A and TOC1, indicating that the expression of these genes may be less directly regulated by GI. ..