Tarsus determination in Drosophila melanogaster.
Arista versus tarsus determination is well investigated in Drosophila, yet it remains unresolved whether Antennapedia (ANTP) cell autonomously or noncell autonomously determines tarsus identity and whether Sex combs reduced (SCR) is the HOX protein required for normal tarsus determination. Three observations rule out a cell autonomous role for ANTP in tarsus determination. (i) Clonal ectopic overexpression of ANTP did not repress the expression of the arista determining protein Homothorax (HTH) in early 3rd stadium antennal imaginal discs. (ii) Clonal ectopic expression of ANTP did not transform the arista to a tarsus. (iii) Ectopic overexpression of ANTP, Labial (LAB), Deformed (DFD), SCR, Ultrabithorax (UBX), Abdominal-A (ABD-A), or Abdominal-B (ABD-B), using the dppGAL4 driver, resulted in arista-to-tarsus transformations, and repressed HTH/Extradenticle (EXD) activity noncell autonomously in early 3rd stadium antennal imaginal discs. SCR may not be the HOX protein required for normal tarsus determination, because co-ectopic expression of Proboscipedia (PB) inhibited the arista-to-tarsus transformations induced by ectopic expression of DFD, SCR, ANTP, UBX, ABD-A, and ABD-B. The proposal that SCR is the HOX protein required for normal tarsus determination is dependent on SCR being the sole target of PB suppression, which is not the case. Therefore, the possibility exists that normal tarsus determination is HOX independent.
Percival-Smith
Anthony
A
Department of Biology, University of Western Ontario, London, Canada. aperciva@uwo.ca
Teft
Wendy A
WA
Barta
Jodi Lynn
JL
D000818:Animals; D051943:Antennapedia Homeodomain Protein / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013643:Tarsus, Animal / Q000254:growth & development / Q000378:metabolism* / Q000648:ultrastructure; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
D051943:Antennapedia Homeodomain Protein; C497974:Antp protein, Drosophila; D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D008164:Luminescent Proteins; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; C059627:Scr protein, Drosophila; D014157:Transcription Factors; C066177:Ubx protein, Drosophila; C409504:blue fluorescent protein, Aequorea victoria; C108704:hth protein, Drosophila; C066591:abd-A protein, Drosophila; D049452:Green Fluorescent Proteins