Figure 2.

Genetic and molecular characterization of unc-70. (A) Genetic map of the unc-70 region. (B) Rescue of unc-70. The cosmid T19F4 rescued the unc-70 phenotype in three out of three lines. An 11.9-kb PCR fragment, only containing the spectrin gene, also rescued the unc-70 phenotype in three out of three lines. Predicted ORFs are shown below. (C) unc-70 cDNAs. Exons are shown as closed boxes and introns as lines. Two splice variants, CeβS1 and CeβS2, are shown. CeβS1 is trans-spliced to the SL1 sequence. The 5′ end of CeβS2 was not determined. (D) cDNA and protein structure comparison. (top) CeβS1 cDNA showing the exon boundaries and the positions of three nonsense alleles induced by ethylmethane sulfonate. unc-70(s1639) is a G to A transition that changes Trp49 to a UAG codon; unc-70(s1502) is a C to T transition that changes Gln576 to a UAA codon; and unc-70(r974) is a G to A transition that changes Trp927 to a UGA codon. (bottom) Domains of the protein. (E) Domain-by-domain comparison of the percent identity between CeβS1, Hsβ2S1, and Drosophila β-spectrin. The NH₂-terminal domain, spectrin repeats, and COOH-terminal domains are indicated below.