Model of the proposed TCP4-mediated repression of AtWRI1 transactivation. A, AtWRI1 activates the expression of target genes for oil biosynthesis by its binding to the AW-box. B to D, The interaction of TCP4 and AtWRI1 results in acting as a repressor of AtWRI1 (binding to promoters of AtWRI1 target genes; B), acting as a repressor of AtWRI1 (not binding to promoters of AtWRI1 target genes; C), or interference of AtWRI1 binding to the promoters of AtWRI1 target genes (D). In any case, the AtWRI1-TCP4 protein complex displays decreased AtWRI1 target transactivation activity as a result of the AtWRI1-TCP4 interaction.