title: A Conserved Structural Signature of the Homeobox Coding DNA in HOX genes.
abstract: The homeobox encodes a DNA-binding domain found in transcription factors regulating key developmental processes. The most notable examples of homeobox containing genes are the Hox genes, arranged on chromosomes in the same order as their expression domains along the body axis. The mechanisms responsible for the synchronous regulation of Hox genes and the molecular function of their colinearity remain unknown. Here we report the discovery of a conserved structural signature of the 180-base pair DNA fragment comprising the homeobox. We demonstrate that the homeobox DNA has a characteristic 3-base-pair periodicity in the hydroxyl radical cleavage pattern. This periodic pattern is significant in most of the 39 mammalian Hox genes and in other homeobox-containing transcription factors. The signature is present in segmented bilaterian animals as evolutionarily distant as humans and flies. It remains conserved despite the fact that it would be disrupted by synonymous mutations, which raises the possibility of evolutionary selective pressure acting on the structure of the coding DNA. The homeobox coding DNA may therefore have a secondary function, possibly as a regulatory element. The existence of such element may have important consequences for understanding how these genes are regulated.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA.|Institute for Translational Sciences, University of Texas Medical Branch, Galveston, TX, USA.
authors.forename: Bernard
authors.initials: B
authors.lastname: Fongang
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA.
authors.forename: Fanping
authors.initials: F
authors.lastname: Kong
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA.
authors.forename: Surendra
authors.initials: S
authors.lastname: Negi
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA.
authors.forename: Werner
authors.initials: W
authors.lastname: Braun
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA.|Institute for Translational Sciences, University of Texas Medical Branch, Galveston, TX, USA.|Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, TX, USA.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Kudlicki
mesh_terms: D000818:Animals; D017124:Conserved Sequence; D004330:Drosophila; D019143:Evolution, Molecular; D005801:Genes, Homeobox / Q000235:genetics*; D006801:Humans; D051379:Mice; D059372:Nucleotide Motifs; D016366:Open Reading Frames