Fig. 5. Characterization of the role of the Zic1-binding site for enhancer activity using electroporation of chick neural tube. (A) The transgenic constructs used in this study (Tg#) and a summary of their activity (ß-gal exp) when electroporated into chick neural tube (EP chick). Each Math1 enhancer fragment was cloned 5' to the promoter region in the BGZA reporter. The numbers in the diagram relate to the published nucleotide sequence of the Math1 enhancer (Accession Number, AF218258). The specific mutations are shown in Fig. 1B. Representative data for each construct are shown in B as cross-sections of chick neural tubes after electroporation and X-gal staining. Electroporated side is always on the right. Arrows indicate expression of the transgene on the electroporated side.