Downregulation of Msx-2 expression results in chondrogenesis in the medial region of the avian mandible.
Homeobox-containing genes are thought to be regulators of pattern formation during vertebrate development. We have previously characterized regions in the developing chick mandible expressing either Msx-1 or Msx-2 in terms of their chondrogenic potential, rates of cell proliferation, and their correlation with regions of cell death. These experiments suggest that Msx-1 may be involved in outgrowth of the mandibular arch, and Msx-2 may be involved in delineating the non-chondrogenic region of the medial part of the mandibular arch. To further examine the possibility that expression of Msx-2 may be involved in preventing chondrogenesis in the medial region, mandibular arch explants from stage 23 chick embryos were cultured for 4 days in media in the absence of serum but in the presence of 20-30 microM Msx-2 sense or antisense oligonucleotides (18 mers). In explants grown in either control media or with the sense oligonucleotide two rods of cartilage separated by a cartilage free area located in the medial region of the mandible were formed. In explants treated with Msx-2 antisense oligonucleotide cartilage formation was observed in the medial region of the mandible resulting in the fusion of the two bilateral rods at the midline. These results suggest a negative relationship between Msx-2 expression and chondrogenesis in the medial region of the developing mandible.
Mina
M
M
Department of Pediatric Dentistry, School of Dental Medicine, University of Connecticut Health Center, Farmington 06030, USA. Mina@nsol.uchc.edu
Gluhak
J
J
Rodgers
B
B
D000818:Animals; D002356:Cartilage / Q000187:drug effects / Q000196:embryology* / Q000378:metabolism; D002642:Chick Embryo; D004268:DNA-Binding Proteins / Q000235:genetics*; D015536:Down-Regulation; D015870:Gene Expression; D018398:Homeodomain Proteins; D008334:Mandible / Q000187:drug effects / Q000196:embryology* / Q000378:metabolism; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D009924:Organ Culture Techniques; D012333:RNA, Messenger / Q000032:analysis
D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; C084119:MSX2 protein; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger