Fig. 3. Deletion and site-directed mutagenesis analyses of ACEL. (A) Deletion analysis of ACEL. Deletions from the 5' end of the ACEL were made with the endogenous lin-3 promoter (constructs 1-4). Deletions from the 5' or the 3' end of the ACEL were generated by PCR and the DNA fragments were fused with a pes-10::gfp enhancer assay vector (constructs 5-8). (B) Site-directed mutagenesis analysis of ACEL. Mutations in the ACEL were generated using PCR and the PCR products were cloned into the pes-10::gfp vector. Construct 1 has no mutations and the others (2-18) have changes in the ACEL as indicated. For each construct, about 30 animals that express gfp in the tail were examined for gfp expression in the AC.