(A) unc-3 exons are indicated as shaded boxes. The n3435 deletion is indicated above exons 2, 3, 4 and 5. (B) The UNC-3 protein is represented with an indication of the location of the protein sequences altered in the e151, n3412, n3413, n3366 and n3435 alleles. Shaded boxes indicate the zinc finger and helix domains.