Point mutation leading to a premature stop codon within alternative exon 18A.
Amino acid replacement: ??term.
G17655764A
W2897term | CadN-PA; W2897term | CadN-PB; W2898term | CadN-PD; W2898term | CadN-PE; W2901term | CadN-PI; W2902term | CadN-PL
W?term
G to A nucleotide change at the second or third position of the wild type Trp codon leads to a nonsense mutation (exact site of mutation unspecified). The mutation was annotated at the second base of the codon. The stop codon falls within alternative exon 18A.
Mutation leads to a stop codon within alternative exon 18A
Single CadNΔ18A mutant R7 clones frequently target to the M3 instead of the M6 layer in medulla neuropil. 84% of the R7 terminals are found in the R8 layer in CadNΔ18A mutant clones. All CadNΔ18A mutant R7 growth cones remain in the correct target layer at both 35% after pupal formation (APF) and 48% APF. In the adult, most CadNΔ18A mutant R7 growth cones are found in the R8 recipient area. At 48% after pupal formation (APF), many R1-R6 cell axons homozygous for CadNΔ18A extend as in wild-type (69%), with almost all finding their correct targets (95%). Only 7% of CadNΔ18A R cell axons do not extend at all. The remaining 24% extend aberrantly, forming thin, branched filopodia that nonetheless follow a normal trajectory. A similar pattern of extension is observed for all R1-R6 subtypes. While the phenotypes observed at this stage is mild, the phenotype observed in the adult is similar to CadN null mutants.
