Role of the Dlx homeobox genes in proximodistal patterning of the branchial arches: mutations of Dlx-1, Dlx-2, and Dlx-1 and -2 alter morphogenesis of proximal skeletal and soft tissue structures derived from the first and second arches

Dev Biol. 1997 May 15;185(2):165-84. doi: 10.1006/dbio.1997.8556.

Abstract

The Dlx homeobox gene family is expressed in a complex pattern within the embryonic craniofacial ectoderm and ectomesenchyme. A previous study established that Dlx-2 is essential for development of proximal regions of the murine first and second branchial arches. Here we describe the craniofacial phenotype of mice with mutations in Dlx-1 and Dlx-1 and -2. The skeletal and soft tissue analyses of mice with Dlx-1 and Dlx-1 and -2 mutations provide additional evidence that the Dlx genes regulate proximodistal patterning of the branchial arches. This analysis also elucidates distinct and overlapping roles for Dlx-1 and Dlx-2 in craniofacial development. Furthermore, mice lacking both Dlx-1 and -2 have unique abnormalities, including the absence of maxillary molars. Dlx-1 and -2 are expressed in the proximal and distal first and second arches, yet only the proximal regions are abnormal. The nested expression patterns of Dlx-1, -2, -3, -5, and -6 provide evidence for a model that predicts the region-specific requirements for each gene. Finally, the Dlx-2 and Dlx-1 and -2 mutants have ectopic skull components that resemble bones and cartilages found in phylogenetically more primitive vertebrates.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Branchial Region / embryology*
  • Branchial Region / metabolism
  • Branchial Region / ultrastructure
  • Craniofacial Abnormalities / genetics
  • Craniofacial Abnormalities / pathology
  • DNA Primers / chemistry
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / physiology*
  • Gene Expression Regulation, Developmental / physiology
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / physiology*
  • Mice
  • Mice, Mutant Strains
  • Morphogenesis / physiology
  • Mutagenesis, Site-Directed
  • Transcription Factors

Substances

  • DNA Primers
  • DNA-Binding Proteins
  • Distal-less homeobox proteins
  • Homeodomain Proteins
  • Tes protein, mouse
  • Transcription Factors