Region-specific expression of murine Hox genes implies the Hox code-mediated patterning of the digestive tract

Authors

  • Tomohisa Sekimoto,

    1. Department of Developmental Genetics, Institute of Molecular Embryology and Genetics, Kumamoto University School of Medicine, 4-24-1 Kuhonji, Kumamoto 862, Japan,
    2. Department of Orthopaedic Surgery, Miyazaki Medical College, 6500 Kihara, Kiyotake, Miyazaki 889-16, Japan
    Search for more papers by this author
  • Kumiko Yoshinobu,

    1. Gene Technology Center, Kumamoto University, 2-2-1 Honjo, Kumamoto 860, Japan,
    Search for more papers by this author
  • Michio Yoshida,

    1. Department of Morphogenesis, Institute of Molecular Embryology and Genetics, Kumamoto University School of Medicine, 2-2-1 Honjo, Kumamoto 860, Japan, and,
    Search for more papers by this author
  • Shigeru Kuratani,

    1. Department of Morphogenesis, Institute of Molecular Embryology and Genetics, Kumamoto University School of Medicine, 2-2-1 Honjo, Kumamoto 860, Japan, and,
    Search for more papers by this author
  • Shoji Fujimoto,

    1. Department of Developmental Genetics, Institute of Molecular Embryology and Genetics, Kumamoto University School of Medicine, 4-24-1 Kuhonji, Kumamoto 862, Japan,
    Search for more papers by this author
  • Masatake Araki,

    1. Gene Technology Center, Kumamoto University, 2-2-1 Honjo, Kumamoto 860, Japan,
    Search for more papers by this author
  • Naoya Tajima,

    1. Department of Orthopaedic Surgery, Miyazaki Medical College, 6500 Kihara, Kiyotake, Miyazaki 889-16, Japan
    Search for more papers by this author
  • Kimi Araki,

    1. Department of Developmental Genetics, Institute of Molecular Embryology and Genetics, Kumamoto University School of Medicine, 4-24-1 Kuhonji, Kumamoto 862, Japan,
    Search for more papers by this author
  • Ken-ichi Yamamura

    1. Department of Developmental Genetics, Institute of Molecular Embryology and Genetics, Kumamoto University School of Medicine, 4-24-1 Kuhonji, Kumamoto 862, Japan,
    2. Gene Technology Center, Kumamoto University, 2-2-1 Honjo, Kumamoto 860, Japan,
    Search for more papers by this author

Ken-ichiYamamura 4-24-1 Kuhonji, Kumamoto 862, Japan. E-mail: yamamura@gpo.kumamoto-u.ac.jp

Abstract

Background

Hox genes encode transcription factors which are involved in the establishment of regional identities along the anteroposterior (AP) body axis. To elucidate the AP patterning of the digestive tract, we have systematically examined the expression patterns of Hox genes belonging to paralogue groups 6, 7, 8 and 9 by whole-mount in situ hybridization and by section in situ hybridization analyses.

Results

The expression patterns of these genes showed co-linearity along the wall of the digestive tract, thereby yielding the Hox code of the gut. The expression boundaries of the Hox genes at later stages (12.5 d.p.c.) corresponded to the morphological boundaries of individual gut subdomains.

Conclusions

The visceral mesoderm-restricted expression suggested that the Hox code primarily functions in the mesenchymal specification which eventually leads to the regional differentiation of gut subdomains as the result of epithelial–mesenchymal interactions. Overlapping expression patterns were found among the paralogous Hox genes, indicating that the paralogues may have redundant functions in the specification of the gut.

Ancillary