MSX2 contains two exons. The length of MSX2 gene is 6328 bases.

2224 bases mRNA; 801 bases of coding region.

One pseudogene was reported (Hodgkinson et al., 1993).

This gene encodes a member of the muscle segment homeobox gene family that consists of 267 amino acids. The molecular weight of the encoded protein is about 29 kDa. MSX2 is a transcriptional repressor which regulates a balance between survival and apoptosis of neural crest-derived cells for proper craniofacial morphogenesis (Davidson, 1995). MSX2 is also shown to be an important target for the RAS signaling pathways (Takahashi et al., 1996). The expression pattern of this gene in the development of organs suggests its pivotal role in epithelial-mesenchymal interactions (Satoh et al., 2004). On the other hand, accumulating evidence has revealed the active involvement of this gene in tumorigenesis and/or tumor development (Satoh et al., 2012).

The expression of MSX2 is observed in a variety of sites, including premigratory cranial neural crest, tooth, and mammary gland, etc (Takahashi and Le Douarin, 1990; Davidson, 1995; Satoh et al., 2004). In addition, enhanced expression of MSX2 is found in several cancer species (Satoh et al., 2012).

Located at cell nuclei.

MSX2 act as a transcriptional regulator in the development multiple organs such as bone, neural crest and mammary gland, and play a role in limb-pattern and teeth formation (Davidson, 1995). MSX2 may induce the proliferation of osteoprogenitors (Dodig et al., 1999), as well as osteoblasts (Liu et al., 1999), and this gene was also related to the enhancement of branching morphogenesis in mouse mammary ducts (Satoh et al., 2007).

Mus musculus Msx2; Xenopus laevis msx2-A; Drosophila melanogaster Dr.

Mutations in this gene are associated with Boston type craniosynostosis (Jabs et al., 1993).