Wilson Joanne, Tucker Abigail S
Craniofacial Development and Orthodontics, King's College London, London SE1 9RT, UK.
Dev Biol. 2004 Feb 1;266(1):138-50. doi: 10.1016/j.ydbio.2003.10.012.
The development of the jaw joint between the palatoquadrate and proximal part Meckel's cartilage (articular) has recently been shown to involve the gene Bapx1. Bapx1 is expressed in the developing mandibular arch in two distinct caudal, proximal patches, one on either side of the head. These domains coincide later with the position of the developing jaw joint. The mechanisms that result in the restricted expression of Bapx1 in the mandibular arch were investigated, and two signaling factors that act as repressors were identified. Fibroblast growth factors (Fgfs) expressed in the oral epithelium restrict expression of Bapx1 to the caudal half of the mandibular arch, while bone morphogenetic proteins (Bmps) expressed in the distal mandibular arch restrict expression of Bapx1 to the proximal part of the mandible. Application of Fgf8 and Bmp4 beads to the proximal mesenchyme led to loss of Bapx1 expression and later fusion of the quadrate and articular as the jaw joint failed to form. In addition to fusion of the jaw joint, loss of Bapx1 lead to loss of the retroarticular process (RAP), phenocopying the defects seen after Bapx1 function was reduced in the zebrafish. By manipulating these signals, we were able to alter the expression domain of Bapx1, resulting in a new position of the jaw joint.
最近研究表明，腭方骨与梅克尔软骨近端（关节骨）之间的颌关节发育涉及基因Bapx1。Bapx1在发育中的下颌弓的两个不同的尾侧近端区域表达，位于头部两侧。这些区域随后与发育中的颌关节位置重合。研究了导致Bapx1在下颌弓中表达受限的机制，并鉴定出两种作为抑制因子的信号因子。口腔上皮中表达的成纤维细胞生长因子（Fgfs）将Bapx1的表达限制在下颌弓的尾侧半部，而下颌弓远端表达的骨形态发生蛋白（Bmps）将Bapx1的表达限制在下颌骨的近端部分。将Fgf8和Bmp4珠应用于近端间充质导致Bapx1表达丧失，随后方骨和关节骨融合，因为颌关节未能形成。除了颌关节融合外，Bapx1的缺失还导致关节后突（RAP）的缺失，这与斑马鱼中Bapx1功能降低后出现的缺陷相似。通过操纵这些信号，我们能够改变Bapx1的表达域，从而使颌关节处于新的位置。
