title: A nonsense mutation within the act88F actin gene disrupts myofibril formation in Drosophila indirect flight muscles.
abstract: We have investigated the molecular basis of muscle abnormalities in the flightless Drosophila mutant lfm(3)7. This EMS-induced, semi-dominant allele was isolated by Mogami and Hotta (1981) and was shown to disrupt the organization of myofibrils in indirect flight muscles. Here we demonstrate that lfm(3)7 contains a nonsense mutation within codon 355 of the act88F actin gene. A single G greater than A transition converts a tryptophan (TGG) codon to an opal (TGA) terminator, thus deleting the carboxy-terminal 20 amino acids of an actin isoform that accumulates only in thoracic flight muscles. The truncated actin polypeptide is stable, and retains antigenicity to at least two anti-Drosophila actin monoclonal antibodies. We suggest that abnormalities in lfm(3)7 flight muscles result from incorporation of the mutant actin isoform into assembling myofibrils.
mesh_terms: D000199:Actins / Q000235:genetics*; D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004330:Drosophila / Q000235:genetics*; D005426:Flight, Animal; D005796:Genes; D005799:Genes, Dominant; D008854:Microscopy, Electron; D024510:Muscle Development; D009132:Muscles / Q000648:ultrastructure*; D009154:Mutation; D009210:Myofibrils / Q000648:ultrastructure*; D009693:Nucleic Acid Hybridization; D014176:Protein Biosynthesis
chemical_list: D000199:Actins