Fig. 5. (A) Schematic of zag-1 GFP translational and transcriptional transgenes. Black boxes depict zag-1 exons, gray boxes represent the GFP gene (coding region and synthetic introns) and white boxes indicate the 3' UTR of unc-54. For neuronal GFP expression: +++, high expression in many head and tail neurons, including head command interneurons, RME, PVT and PVQ; ++, high expression in similar set of neurons, excluding head command interneurons; +, low expression in five or fewer neurons in head. For muscle GFP expression: +, high expression in anal depressor and intestinal muscles; #, transient, high expression in body wall muscles; -, no muscle expression. For zag-1(lf) derepression: +, high expression in command interneurons and VNC motor neurons; -, no expression in command interneurons and VNC motor neurons. Regions required for downregulation of zag-1 expression, muscle expression, neuronal expression and ZAG-1-mediated repression are indicated. The caret indicates the location of tandem CACCT site. (B) Alignment of CACCT and adjacent sequences present in C. elegans (C. e.) and C. briggsae (C. b.) zag-1 genomic region. Nucleotides altered in promoter mutants are indicated above the sequence.