title: Iroquois transcription factors recognize a unique motif to mediate transcriptional repression in vivo.
abstract: Iroquois transcription factors regulate diverse aspects of developmental patterning in all metazoans. Despite their widespread importance, the direct targets of the Iroquois are poorly understood. Here, we use in vitro site selection to define the DNA-binding preference of the Drosophila Iroquois Mirror. We use electrophoretic mobility shift assays to determine the critical nucleotides for Mirror binding and to show that this site is recognized by other Drosophila Iroquois transcription factors. This site also is recognized by vertebrate Iroquois transcription factors. Transgenic analysis demonstrates that Drosophila Iroquois proteins recognize this site in vivo to mediate transcriptional repression. We further show that Iroquois transcription factors form homodimers and heterodimers, suggesting that combinatorial binding may contribute to gene regulation by this family.
authors.affiliation: London Research Institute, Cancer Research UK, London WC2A 3PX, United Kingdom.
authors.forename: Aphrodite
authors.initials: A
authors.lastname: Bilioni
authors.forename: Gavin
authors.initials: G
authors.lastname: Craig
authors.forename: Caroline
authors.initials: C
authors.lastname: Hill
authors.forename: Helen
authors.initials: H
authors.lastname: McNeill
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004247:DNA / Q000378:metabolism*; D019281:Dimerization; D004330:Drosophila; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D008156:Luciferases; D008969:Molecular Sequence Data; D017351:N-Acetylglucosaminyltransferases / Q000378:metabolism; D009841:Oligonucleotides; D011485:Protein Binding; D016415:Sequence Alignment; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; D005136:Eye Proteins; D018398:Homeodomain Proteins; D009841:Oligonucleotides; D014157:Transcription Factors; C105790:mirr protein, Drosophila; D004247:DNA; D008156:Luciferases; D017351:N-Acetylglucosaminyltransferases; C090576:fng protein, Drosophila