Amino acid replacement: W142term.
G16679882A
W142term | sing-PA
W142term
G to A nucleotide change at the second or third position of the Trp codon leads to a nonsense mutation (exact site of mutation unspecified). Site of nucleotide substitution in mutant inferred by FlyBase based on reported amino acid change.
Stage 14 homozygous embryos have unfused groups of myoblasts, reminiscent of a "bunch of grapes" phenotype (wild-type embryos have no unfused myoblasts at this stage).
Stage 12 homozygous embryos contain the normal number of Kr-positive founder cells and lmd-positive fusion-competent myoblasts.
DA1 muscles are uniformly binucleate in homozygous stage 16 embryos (wild-type DA1 muscles contain 9-14 nuclei at this stage).
Ultrastructural analysis of adhering myoblasts that are in the process of fusing in homozygous embryos indicates that they contain pre-fusion complexes (electron-dense vesicles paired on either side of the fusing plasma membranes) as occurs in wild-type embryos. However, the number of pre-fusion complexes in the myoblasts of late stage 12/early stage 13 mutant embryos is significantly higher than in wild-type embryos; on average 48% of mutant myoblasts contain pre-fusion complexes compared to 22% of wild-type myoblasts. The total number of vesicles pr pre-fusion complex is slightly but significantly higher in the mutant embryos compared to wild type.
sing23 is rescued by sing+t2.524
sing23 is rescued by Scer\GAL4twi.PG/singUAS.cEa