| Modification Notes |
Msx homeobox genes encode for transcription factors that control morphogenesis and are expressed at sites of epithelial-mesenchymal interaction during embryogenesis, such as the tooth (1,2). Two of these genes, Msx-1 and Msx-2, are key factors for the development of tooth and craniofacial skeleton (2,3). Msx-1 also down-regulates a master gene of skeletal cells differentiation (3). Msx-1 and Msx-2 contribute to the initial patterning of dentition as well as playing a pivotal role in terminal cell differentiation (1). In addition, Msx-1 and Msx-2 are expressed in the epidermis, hair follicles and fibroblasts of the developing fetal skin (4). In adult skin, Msx-1 and Msx-2 expression is confined to epithelially derived structures (4). Msx-2 is detected as a diffuse cytoplasmic signal in fetal epidermis and portions of the hair follicle and dermis, but is localized to the nucleus in the adult epidermis (4). Msx-1 and Msx-2 are also expressed during critical developmental stages of neural tube and neural crest, suggesting that these genes play an important role in organogenesis (5). |