Fig. 4. Characterization of SPCG salivary gland enhancers identifies at least three CrebA-dependent enhancers. Reporter gene constructs were built for six of the 34 SPCGs analyzed in this study (A-F, diagrams at the top). Yellow circles of each set of embryos indicate the consensus motif found in SPCGs by MEME analysis. Arrows indicate putative transcription start sites based on the longest sequenced 5' end cDNAs for each gene. Green lines indicate the open reading frames. Three independent lines carrying the srp68 lacZ construct did not have ß-gal expression in the salivary gland (A). Multiple independent lines carrying p24-1 lacZ, srpR lacZ and zcop lacZ constructs showed salivary gland ß-gal expression beginning during embryonic stage 13 and continuing through the rest of embryogenesis (B-D). Independent lines carrying the spase25 lacZ (F) and sec61ß lacZ (E) constructs had ß-gal salivary gland staining from early stage 12 through the rest of embryogenesis (E,F). The zcop and sec61ß lacZ constructs that gave salivary gland expression of ß-gal in wild-type embryos did not express ß-gal in the salivary glands of CrebA mutants (D,E, lower two rows). The spase25 lacZ constructs showed significantly reduced expression in the salivary glands of CrebA mutants (F, lower two rows).