THE EXPRESSION OF MSX GENES DURING EARLY CRANIAL SUTURE EMBRYOGENESIS

두개골 봉합부의 초기 형태발생과정에서 Msx 유전자들의 발현양상

  • Lee, Sang-Youp (Department of Pediatric Dentistry, College of Dentistry, Kyungpook National University) ;
  • Park, Mi-Hyun (Department of Oral Biochemistry, College of Dentistry, Kyungpook National University) ;
  • Ryoo, Hyun-Mo (Department of Oral Biochemistry, College of Dentistry, Kyungpook National University) ;
  • Nam, Soon-Hyeun (Department of Pediatric Dentistry, College of Dentistry, Kyungpook National University) ;
  • Kim, Young-Jin (Department of Pediatric Dentistry, College of Dentistry, Kyungpook National University) ;
  • Kim, Hyun-Jung (Department of Pediatric Dentistry, College of Dentistry, Kyungpook National University)
  • 이상엽 (경북대학교 소아치과학교실) ;
  • 박미현 (경북대학교 구강생화학교실) ;
  • 유현모 (경북대학교 구강생화학교실) ;
  • 남순현 (경북대학교 소아치과학교실) ;
  • 김영진 (경북대학교 소아치과학교실) ;
  • 김현정 (경북대학교 소아치과학교실)
  • Published : 2003.02.28

Abstract

The development of calvarial bones is tighly co-ordinated with the growth of the brain and needs of harmonious interactions between different tissues within the calvarial sutures. Premature fusion of cranial sutures, known as craniosynostosis, presumably involves disturbance of these interactions. Mutations in the homeobox-containg gene Msx2 cause human craniosynostosis syndrome. Msx genes, which are consist of Msx1, Msx2 and Msx3, are homeobox-containg transcripton factors, and were originally identified as homologue of Drosophila msh(muscle segment homeobox) gene. Msx1 and Msx2 genes, expressed mostly in overlapping patterns at multiple site of tissue interactions during vertebrate development, are associated with epithelial-mesenchymal interactions during organogenesis, targets of BMP and FGF signaling. To elucidate the function of Msx genes in the early morphogenesis of mouse cranial suture, we analyzed the expression of them by in situ hybridization during embryonic(E15-E18) stage, and did vivo experiments in E15.5 mouse using rhBMP-2, rhFGF-2 protein soaked bead. In the sagittal suture, Msx1 was expressed in the mesenchyme of suture and the dura mater, Msx2 was intensely expressed in the sutural mesenchyme and the dura mater. In the coronal suture both of Msx genes were expressed intensely in the sutural mesenchyme and expressed in the periosteum also. Msx1 had a broader expression pattern than Msx2. BMP2 beads induced expression of both Msx1 and Msx2, FGF2 beads induced expression of Msx1, but not Msx2. Taken together, these data suggest that Msx1 and Msx2 genes have important role in regulating the morphogenesis and maintenance of embryonic cranial suture. Both of Msx genes are expressed similarly but because of their upstream signaling, they function dependently or cooperatively according to change of signaling molecule.