Functional dissection of multiplexed sequences reveals key motifs. (a) We tested three deletion mutants for each of the four tissue-specific multiplexed sequences, using the first (L9, peach), middle (M9, green) and last (R9, blue) 9 bp of each sequence cloned between the same flanking sequences. (b) With one exception (2GH12/notochord), a 9-bp sequence was sufficient to drive the expression pattern of the original multiplexed construct. Percentages of fish expressing in the appropriate tissue at 24 hpf are shown, with the value for the functional 9-mer highlighted in black. The top-matching position weight-matrix identified by Tomtom  is listed for each construct.
Smith et al. Genome Biology 2013 14:R72 doi:10.1186/gb-2013-14-7-r72