Complex genetic interactions govern the temporal effects of Antennapedia on antenna-to-leg transformations in Drosophila melanogaster.
The putative regulatory relationships between Antennapedia (Antp), spalt major (salm) and homothorax (hth) are tested with regard to the sensitive period of antenna-to-leg transformations. Although Antp expression repressed hth as predicted, contrary to expectations, hth did not show increased repression at higher Antp doses, whereas salm, a gene downstream of hth, did show such a dose response. Loss of hth allowed antenna-to-leg transformations but the relative timing of proximal-distal transformations was reversed, relative to transformations induced by ectopic Antp. Finally, overexpression of Hth was only partially able to rescue transformations induced by ectopic Antp. These results indicate that there may be additional molecules involved in antenna/leg identity and that spatial, temporal and dosage relationships are more subtle than suspected and must be part of a robust understanding of molecular network behaviour involved in determining appendage identity in Drosophila melanogaster.
Dworkin
Ian
I
Department of Zoology, University of Toronto, 25 Herbord St., Toronto, Ontario M5S 3G5, Canada. idworkin@msu.edu
Lee
Wendy
W
McCloskey
Fiona
F
Larsen
Ellen
E
D000818:Animals; D030801:Animals, Genetically Modified; D051943:Antennapedia Homeodomain Protein / Q000235:genetics* / Q000502:physiology*; D019521:Body Patterning / Q000235:genetics; D029721:Drosophila Proteins / Q000235:genetics* / Q000502:physiology*; D004331:Drosophila melanogaster / Q000196:embryology* / Q000235:genetics*; D004625:Embryo, Nonmammalian; D018628:Gene Dosage / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D053263:Gene Regulatory Networks / Q000502:physiology; D005816:Genetic Complementation Test; D018398:Homeodomain Proteins / Q000235:genetics; D017880:Limb Deformities, Congenital / Q000235:genetics*; D008954:Models, Biological; D013997:Time Factors
D051943:Antennapedia Homeodomain Protein; C497974:Antp protein, Drosophila; D029721:Drosophila Proteins; D018398:Homeodomain Proteins; C108704:hth protein, Drosophila