Fig. 5-. Regulatory gene interactions (S. purpuratus).

Tiers of regulatory genes are shown top-to-bottom in their approximate order of activation. Genes in gray box represent regulatory genes expressed selectively by PMCs that currently have no regulatory linkages to any other genes in the PMC GRN. Experimental evidence for the regulatory linkages shown comes primarily from Oliveri et al. (2008) and Rafiq et al. (2014), with additional information from Wahl et al., (2009), Sharma and Ettensohn (2010), Damle and Davidson (2011), Rho and McClay (2011), and Rafiq et al. (2012). Notes: (a) MAPK signaling, activated autonomously in the PMC lineage by unknown mechanisms, is required for Ets1 function. (b) Inputs from Ets1 and Tgif into alx1 occur several hours after alx1 activation. (c) The input from Ets1 into tbr occurs late (post-ingression). (d) The input from Tbr into foxN2/3 is extrapolated from data for L. variegatus. (e) Inputs from Hex and Tgif into foxO are evident at 24 hpf but not at 18 hpf. See Fig. 1 for description of symbols.