Evidence for a direct functional antagonism of the selector genes proboscipedia and eyeless in Drosophila head development.
Diversification of Drosophila segmental and cellular identities both require the combinatorial function of homeodomain-containing transcription factors. Ectopic expression of the mouthparts selector proboscipedia (pb) directs a homeotic antenna-to-maxillary palp transformation. It also induces a dosage-sensitive eye loss that we used to screen for dominant Enhancer mutations. Four such Enhancer mutations were alleles of the eyeless (ey) gene that encode truncated EY proteins. Apart from eye loss, these new eyeless alleles lead to defects in the adult olfactory appendages: the maxillary palps and antennae. In support of these observations, both ey and pb are expressed in cell subsets of the prepupal maxillary primordium of the antennal imaginal disc, beginning early in pupal development. Transient co-expression is detected early after this onset, but is apparently resolved to yield exclusive groups of cells expressing either PB or EY proteins. A combination of in vivo and in vitro approaches indicates that PB suppresses EY transactivation activity via protein-protein contacts of the PB homeodomain and EY Paired domain. The direct functional antagonism between PB and EY proteins suggests a novel crosstalk mechanism integrating known selector functions in Drosophila head morphogenesis.
Benassayag
Corinne
C
Centre de Biologie du Développement-CNRS and Institut d'Exploration Fonctionnelle du Génome, 118 route de Narbonne, Bâtiment 4R3, F-31062 Toulouse Cedex 04, France.
Plaza
Serge
S
Callaerts
Patrick
P
Clements
Jason
J
Romeo
Yves
Y
Gehring
Walter J
WJ
Cribbs
David L
DL
D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004247:DNA / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000502:physiology; D004330:Drosophila / Q000235:genetics* / Q000254:growth & development*; D029721:Drosophila Proteins / Q000235:genetics* / Q000502:physiology; D005124:Eye Abnormalities / Q000235:genetics; D005260:Female; D018507:Gene Expression Regulation, Developmental; D005801:Genes, Homeobox; D017344:Genes, Insect; D006257:Head / Q000254:growth & development; D018398:Homeodomain Proteins / Q000235:genetics* / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D008437:Maxilla / Q000254:growth & development; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D014157:Transcription Factors / Q000235:genetics* / Q000502:physiology; D015533:Transcriptional Activation; D020798:Two-Hybrid System Techniques
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D014157:Transcription Factors; C113278:ey protein, Drosophila; C096658:pb protein, Drosophila; D004247:DNA