Drosophila projectin: relatedness to titin and twitchin and correlation with lethal(4) 102 CDa and bent-dominant mutants.
We have investigated projectin, a large protein of insect muscles, in Drosophila melanogaster. The 5.3 kilobases of coding sequence reported here contains Class I and Class II motifs characteristic of titin and twitchin, arranged in a three domain ... [II-I-I] [II-I-I] ... pattern. Two mutants mapped to the location of the projectin gene in the 102C subdivision of chromosome 4, lethal(4) 102 CDa and bent-Dominant, have DNA rearrangements within their projectin gene. The lethal(4) 102 CDa mutant has a 141 nucleotide insertion containing stop codons in all three reading frames within an exon sequence, showing that it cannot synthesize normal projectin. Both bent-Dominant and lethal(4) 102 CDa homozygotes die at the completion of embryogenesis because they are unable to escape the egg vitelline membrane. We propose that this hatching failure is due to muscle weakness caused by projectin defects.
Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218.
C C
CC
Fyrberg
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Labeit
B
B
Bullard
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K
Leonard
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Fyrberg
D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D029742:Caenorhabditis elegans Proteins; D002148:Calmodulin-Binding Proteins; D003001:Cloning, Molecular; D064211:Connectin; D004331:Drosophila melanogaster / Q000235:genetics*; D005799:Genes, Dominant; D005804:Genes, Lethal; D015801:Helminth Proteins / Q000235:genetics*; D008565:Membrane Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000235:genetics*; D009154:Mutation; D011494:Protein Kinases; D017385:Sequence Homology
D029742:Caenorhabditis elegans Proteins; D002148:Calmodulin-Binding Proteins; D064211:Connectin; D015801:Helminth Proteins; D008565:Membrane Proteins; D009124:Muscle Proteins; C078033:projectin; C489233:unc-22 protein, C elegans; D011494:Protein Kinases