Fig. 1. Wild-type and mutant Hts protein domains and expression. (A,B) For each wild-type and mutant protein, the Flybase designation, Whittaker mRNA designation (Whittaker et al., 1999), predicted size, RNA expression and protein localization are given. (A) All wild-type proteins contain the Head (H) and Neck (N) domains of Adducin (homology shown in red). ShAdd contains a truncated Tail (T) domain and then 23 novel amino acids at its C-terminus (purple). Ovhts, Add1 and Add2 share a common Tail. Alternative splicing at the codon for amino acid 658 (circled) results in three transcripts with different C-terminal domains. Ovhts has a novel domain designated the RC domain (blue). Add1 and Add2 maintain homology to mammalian Add, with Add2 splicing into an exon encoding 23 amino acids and both encoding the C-terminal MARCKS domain. The regions used as antigens for antibody production are underlined. (B) Two truncation mutants lack the wild-type C-terminal domains. hts^G has a single base pair deletion of G2346 resulting in a frameshift, six novel amino acids and a premature stop codon. In hts^W532X Trp532 of both Ovhts and Add is mutated to a stop codon in the Tail domain.