The design and analysis of a homeotic response element.
We have shown that the 26 bp bx1 element from the regulatory region of Distal-less is capable of imposing control by the homeotic genes Ultrabithorax and abdominal-A on a general epidermal activator in Drosophila. This provides us with an assay to analyze the sequence requirements for specific repression by these Hox genes. Both the core Hox binding site, 5'-TAAT, and the adjacent EXD 5'-TGAT core site are required for repression by Ultrabithorax and abdominal-A. The Distal-less bx1 site thus fits with the model of Hox protein binding specificity based on the consensus PBX/HOX-family site TGATNNAT[g/t][g/a], where the key elements of binding specificity are proposed to lie in the two base pairs following the TGAT. A single base pair deletion in the bx1 sequence generates a site, bx1:A(-)mut, that on the consensus PBX/HOX model would be expected to be regulated by the Deformed Hox gene. We observed, however, that the bx1:A(-)mut site was regulated predominantly by Sex combs reduced, Ultrabithorax and abdominal-A. The analysis of this site indicates that the specificity of action of Hox proteins may depend not only on selective DNA binding but also on specific post-binding interactions.
White
R A
RA
Department of Anatomy, University of Cambridge, Downing Street, Cambridge, UK. rw108@cam.ac.uk
Aspland
S E
SE
Brookman
J J
JJ
Clayton
L
L
Sproat
G
G
D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004330:Drosophila / Q000196:embryology; D029721:Drosophila Proteins; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D020218:Response Elements; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D019476:Insect Proteins; D009687:Nuclear Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; C066177:Ubx protein, Drosophila; C117261:distal-less protein, insect; C083405:exd protein, Drosophila; C066591:abd-A protein, Drosophila