Consistent with these defects,Satb2expression was detected in the tongue and mandible

Consistent with these defects,Satb2expression was detected in the tongue and mandible. during early embryogenesis. A multitude of transcription factors and signalling molecules regulate these processes and disruption in any of these are potential causes of human craniofacial disease. It is therefore not surprising that craniofacial anomalies account for over 70% of congenital malformations, the most common being orofacial clefts that collectively have a prevalence of 1 1 in 500-2500 live births (Vanderas, 1987;Murray et al., 1997;Croen et al., 1998;Murray, 2002;Stanier and Moore, 2004). Craniofacial defects result in considerable morbidity to affected families because individuals exhibiting these conditions experience problems with feeding, speaking, hearing and social integration (Schutte and Murray, 1999). The frequent occurrence and major healthcare burden imposed by craniofacial malformations highlight the need to dissect the aetiology and molecular pathogenesis of these conditions. A combination of cytogenetic and sequence analyses has recently indicated that mutation of the gene encodingSpecial AT-rich Sequence Binding Protein 2(SATB2) results in a combination of isolated cleft palate, micrognathia, digit malformations, dental anomalies, osteoporosis and learning difficulties in humans (FitzPatrick et al., 2003;Leoyklang et al., 2007;Rosenfeld et al., 2009;Urquhart et al., 2009). Similarly, targeted mutagenesis ofSatb2in mouse MK-3903 leads to craniofacial malformations that are strikingly similar to those observed in patients carryingSATB2mutations (Britanova et al., 2006;Dobreva et al., 2006). Analysis ofSatb2mutant mice indicated that Satb2 regulates craniofacial patterning and osteoblast differentiation (Britanova et al., 2006;Dobreva et al., 2006). To provide further insights into the role of SATB2 during development, we have analyzed the expression pattern ofSatb2during craniofacial development in a range of evolutionary divergent species. Vertebrates such as human, mouse and chick, form six pharyngeal arches; the face forming mainly from the first pharyngeal arch from which the upper jaw, lower jaw and palate arise. Development of the lip and primary palate in both the mouse GLUR3 and chick closely parallels that observed in human. The first signs of overt development of the primary palate occur on embryonic day (E) 9.5 in the mouse and E4 in the chick with formation of the frontonasal MK-3903 prominence, paired maxillary processes, and paired mandibular processes which surround the primitive oral cavity. Formation of the nasal placodes subsequently divides the lower portion of the frontonasal prominence into paired medial and lateral nasal processes. Merging of the facial processes results in the upper lip becoming continuous by E11.5 in the mouse and E6-E7 in the chick. In mice, palatal shelves initiate from the maxillary processes on E11 and MK-3903 grow vertically, lateral to the tongue, during E12 and E13. At E14.5, the palatal shelves re-orientate and make contact above the tongue. The medial edge epithelia of MK-3903 the apposed shelves adhere to form a midline epithelial seam which subsequently degenerates to allow mesenchymal continuity across the palate by E15 (Gritli-Linde, 2007). In contrast, although chick palatal shelves grow towards one another above the tongue and contact at around E7-E9, they remain cleft rather than fusing (Shah and Crawford, 1980). While the mouse therefore MK-3903 provides an excellent system in which to study normal development of the secondary palate, the chick mirrors the pathology seen in cleft palate. Zebrafish are also an important model in which to study craniofacial development. Many of the signalling pathways crucial for formation of the head and face are highly conserved between zebrafish and higher vertebrates (Yelick and Schilling, 2002;Clouthier and Schilling, 2004). Recent evidence also suggests that the zebrafish anterior neurocranium.