A homeodomain point mutation of the Drosophila proboscipedia protein provokes eye loss independently of homeotic function.
The Drosophila homeotic gene proboscipedia (pb: HoxA2/B2 homolog) is required for adult mouthparts development. Ectopic PB protein expression from a transgenic Hsp70-pb minigene (HSPB) results in transformation of adult antennae to maxillary palps. In contrast, most tissues appear refractory to PB-induced effects. To study the basis of homeotic tissue specificity we are isolating and studying mutations that modify dominant HSPB-induced phenotypes. One HSPB point mutation (Arg5 of the homeodomain to His) removes homeotic activity in the mouthparts and antennae, but provokes a dose-sensitive eye loss. We show that eye loss can be induced by PB proteins that no longer effectively bind to DNA. The dose-sensitive eye loss thus appears to be mediated by specific, context-dependent protein-protein interactions.
Benassayag
C
C
Centre de Biologie du Développement-CNRS, Toulouse, France.
Seroude
L
L
Boube
M
M
Erard
M
M
Cribbs
D L
DL
D000595:Amino Acid Sequence; D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004330:Drosophila / Q000235:genetics*; D029721:Drosophila Proteins; D005123:Eye / Q000196:embryology / Q000378:metabolism; D005124:Eye Abnormalities / Q000235:genetics*; D018628:Gene Dosage; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D017354:Point Mutation; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D019076:Transgenes / Q000502:physiology
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D006360:Heat-Shock Proteins; D018398:Homeodomain Proteins; D014157:Transcription Factors; C096658:pb protein, Drosophila