Figure 5. Bcd requires C-terminal protein domains to bind to concentration-sensitive targets.

(A) GFP-Bcd⁰⁸⁵ construct is truncated within the S/T domain downstream of the homedomain. Wild-type protein domains modified from (Janody et al., 2001) and (Crauk and Dostatni, 2005). The N-terminus of the protein includes a PRD repeat, followed by the DNA-binding homeodomain (HD) (Berleth et al., 1988). The serine/threonine-rich (S/T) domain is the target of MAPK phosphorylation by the terminal patterning Torso pathway (Janody et al., 2000) and contains a PEST sequence implicated in targeting the protein for degradation (Rechsteiner and Rogers, 1996). The C-terminus contains three domains implicated in transcriptional activation. The glutamine-rich (Q)/OPA and alanine-rich (A) domains are required for interactions with TAFII110 and TAFII60, respectively (Sauer et al., 1995). The acidic (C) domain has been demonstrated to play a role in transcriptional activation in yeast, but is not required for Bcd activity in the embryo (Driever et al., 1989). (B) GFP-Bcd⁰⁸⁵ forms a protein gradient comparable to wild-type GFP-Bcd. GFP fluorescence intensity was extracted from dorsal profiles of live embryos. Error bars are standard error of the mean: GFP-Bcd embryos, n = 8; and GFP-Bcd⁰⁸⁵ embryos, n = 8. (C) Boxplots displaying log transformed CPM normalized ChIP-seq data from GFP-Bcd;;bcd^E1 (wild-type) and GFP-Bcd⁰⁸⁵;bcd^E1 (Bcd⁰⁸⁵) embryos show significant reduction binding of Bcd⁰⁸⁵ in Concentration-Sensitive I and II peaks. P-values were calculated from permutation tests (n = 10,000).