title: Specificity of Distalless repression and limb primordia development by abdominal Hox proteins.
abstract: In Drosophila, differences between segments, such as the presence or absence of appendages, are controlled by Hox transcription factors. The Hox protein Ultrabithorax (Ubx) suppresses limb formation in the abdomen by repressing the leg selector gene Distalless, whereas Antennapedia (Antp), a thoracic Hox protein, does not repress Distalless. We show that the Hox cofactors Extradenticle and Homothorax selectively enhance Ubx, but not Antp, binding to a Distalless regulatory sequence. A C-terminal peptide in Ubx stimulates binding to this site. However, DNA binding is not sufficient for Distalless repression. Instead, an additional alternatively spliced domain in Ubx is required for Distalless repression but not DNA binding. Thus, the functional specificities of Hox proteins depend on both DNA binding-dependent and -independent mechanisms.
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Columbia University, 701 West 168th Street, HHSC 1104, New York, NY 10032, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Gebelein
authors.forename: Joaquim
authors.initials: J
authors.lastname: Culi
authors.forename: Hyung Don
authors.initials: HD
authors.lastname: Ryoo
authors.forename: Wen
authors.initials: W
authors.lastname: Zhang
authors.forename: Richard S
authors.initials: RS
authors.lastname: Mann
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D051943:Antennapedia Homeodomain Protein; D004268:DNA-Binding Proteins / Q000235:genetics*; D004330:Drosophila / Q000196:embryology / Q000235:genetics*; D029721:Drosophila Proteins / Q000235:genetics*; D005121:Extremities / Q000196:embryology; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics*; D019476:Insect Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D051943:Antennapedia Homeodomain Protein; C497974:Antp protein, Drosophila; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D019476:Insect Proteins; D009687:Nuclear Proteins; D014157:Transcription Factors; C066177:Ubx protein, Drosophila; C117261:distal-less protein, insect