Fig. 4. In vitro binding of LAG-1/CSL and ELT-2/GATA to enh^A sequences. (A) Electrophoretic mobility shift assay (EMSA) using GST::LAG-1 and a previously described probe that binds LAG-1 through two CSL-binding sites (Hwang et al., 2007); arrowhead indicates free probe. Competitor DNA is from enh^A (see Fig. 2B). 2-CSL and 3-CSL indicate wild-type sites; 2-CSL^* and 3-CSL^* are ATGGGAA to AAGGCAA and GTGGGAA to GAGGCAA mutations, respectively. (B) EMSA using in vitro translated ELT-2 and a labeled probe from the pho-1 endodermal enhancer (Fukushige et al., 2003). Competitor DNA is the same as in A. 2-GATA and 3-GATA are the wild-type sites; 2-GATA^* and 3-GATA^* are mutations from GATA to CATA. Note that competition with the [2-GATA 3-GATA^*] probe is approximately fivefold less than with the [2-GATA^* 3-GATA] probe.