Picture from Gaudet J et al. (2004) PLoS Biol "Whole-genome analysis of temporal gene expression during foregut ...."
Figure 6. Early-1 and Early-2 Elements Are Required for K07C11.4 Expression. (A) A portion of the promoter sequence of K07C11.4 from C. elegans (bottom) aligned with its ortholog from C. briggsae (top). Boxed regions show conserved predicted PHA-4 binding sites and Early-1 and Early-2 elements. Site-directed mutations that disrupt Early-1 and Early-2 (E2 + E1 Mut) are shown below their respective wild-type (E2 + E1 WT) sequence from K07C11.4. (B-E) Confocal images of mid-stage embryos expressing GFP under the control of the wild-type K07C11.4 promoter (B) or promoters with a mutation in Early-1 (C), Early-2 (D), or both Early-1 and Early-2 (E). Percentages are the fraction of transgenic embryos expressing GFP; the remainder of embryos do not express GFP. (F) Expression of the wild-type K07C11.4 reporter in a subset of somatic gonad cells in an L4 animal (arrowheads). (G) Mutation of the Early-1 element eliminates gonadal expression but does not strongly affect expression in other tissues, such as intestinal cells (arrows). Dashed lines indicate the outline of the developing pharynx.