title: Characterization of the DNA-binding properties of the Mohawk homeobox transcription factor.
abstract: The homeobox transcription factor Mohawk (Mkx) is a potent transcriptional repressor expressed in the embryonic precursors of skeletal muscle, cartilage, and bone. MKX has recently been shown to be a critical regulator of musculoskeletal tissue differentiation and gene expression; however, the genetic pathways through which MKX functions and its DNA-binding properties are currently unknown. Using a modified bacterial one-hybrid site selection assay, we determined the core DNA-recognition motif of the mouse monomeric Mkx homeodomain to be A-C-A. Using cell-based assays, we have identified a minimal Mkx-responsive element (MRE) located within the Mkx promoter, which is composed of a highly conserved inverted repeat of the core Mkx recognition motif. Using the minimal MRE sequence, we have further identified conserved MREs within the locus of Sox6, a transcription factor that represses slow fiber gene expression during skeletal muscle differentiation. Real-time PCR and immunostaining of in vitro differentiated muscle satellite cells isolated from Mkx-null mice revealed an increase in the expression of Sox6 and down-regulation of slow fiber structural genes. Together, these data identify the unique DNA-recognition properties of MKX and reveal a novel role for Mkx in promoting slow fiber type specification during skeletal muscle differentiation.
authors.affiliation: School of Life Sciences, Biodesign Institute, Arizona State University, Tempe, Arizona 85287-4501; Molecular and Cellular Biology Graduate Program, Biodesign Institute, Arizona State University, Tempe, Arizona 85287-4501.
authors.forename: Douglas M
authors.initials: DM
authors.lastname: Anderson
authors.affiliation: School of Life Sciences, Biodesign Institute, Arizona State University, Tempe, Arizona 85287-4501; Molecular and Cellular Biology Graduate Program, Biodesign Institute, Arizona State University, Tempe, Arizona 85287-4501.
authors.forename: Rajani
authors.initials: R
authors.lastname: George
authors.affiliation: Program in Gene Function and Expression, University of Massachusetts Medical School, Worcester, Massachusetts 01605; Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605.
authors.forename: Marcus B
authors.initials: MB
authors.lastname: Noyes
authors.affiliation: School of Life Sciences, Biodesign Institute, Arizona State University, Tempe, Arizona 85287-4501; Molecular and Cellular Biology Graduate Program, Biodesign Institute, Arizona State University, Tempe, Arizona 85287-4501.
authors.forename: Megan
authors.initials: M
authors.lastname: Rowton
authors.affiliation: Department of Biomedical Genetics and Center for Oral Biology, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642.
authors.forename: Wenjin
authors.initials: W
authors.lastname: Liu
authors.affiliation: Department of Biomedical Genetics and Center for Oral Biology, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642.
authors.forename: Rulang
authors.initials: R
authors.lastname: Jiang
authors.affiliation: Program in Gene Function and Expression, University of Massachusetts Medical School, Worcester, Massachusetts 01605; Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605.
authors.forename: Scot A
authors.initials: SA
authors.lastname: Wolfe
authors.affiliation: School of Life Sciences, Biodesign Institute, Arizona State University, Tempe, Arizona 85287-4501.
authors.forename: Jeanne
authors.initials: J
authors.lastname: Wilson-Rawls
authors.affiliation: School of Life Sciences, Biodesign Institute, Arizona State University, Tempe, Arizona 85287-4501; Center for Evolutionary Medicine and Informatics, Biodesign Institute, Arizona State University, Tempe, Arizona 85287-4501. Electronic address: alan.rawls@asu.edu.
authors.forename: Alan
authors.initials: A
authors.lastname: Rawls
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D004247:DNA / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology*; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000166:cytology / Q000378:metabolism*; D041681:NIH 3T3 Cells; D011485:Protein Binding; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D020218:Response Elements / Q000502:physiology*; D055755:SOXD Transcription Factors / Q000096:biosynthesis / Q000235:genetics
chemical_list: D018398:Homeodomain Proteins; D009124:Muscle Proteins; D012097:Repressor Proteins; D055755:SOXD Transcription Factors; C095939:Sox6 protein, mouse; C510657:mohawk protein, mouse; D004247:DNA