ODONTOGENIC CELL LINES FROM IMMORTO-MOUSE

细胞系的可用性一直是研究的核心， 发育、细胞和分子生物学。 几名研究者 已经尝试将牙源性细胞（成釉细胞，成牙本质细胞， 成牙骨质细胞）在文化中取得了一定程度的成功，虽然 一些人试图产生来源于 牙髓细胞（Sato和Ozawa，1975;春日井等，1988）和釉质器官 上皮细胞（Chen等，1992），这些细胞系中没有一个被 证明能够产生矿化基质。 携带SC 40株tsA 58早期区域编码的转基因小鼠 小鼠主要组织相容性复合体控制下的序列 H-2Kb I类启动子现在可从Charles River获得。 这 启动子在身体的不同组织中以各种水平有活性， 在干扰素（IFN）的存在下， 几乎所有的细胞 这些转基因小鼠（H-2Kb-tsA 58）具有潜在的 从任何不同的组织中产生细胞系， 在γ-干扰素存在下， 允许的温度，然后通过去除 诱导剂并保持在非允许温度下（Jan等人，1991）。 来源于皮肤成纤维细胞的细胞系（Jat et al，1991），破骨细胞 细胞（Chambers等，1993）、结肠和小肠上皮细胞 （Whitehead等，1993）和星形胶质细胞（格罗夫斯等，1993），使用 已经描述了H-2Kb-tsA 58转基因小鼠。 在这项研究中，我们提出了测试的假设，牙乳头， 从H-2Kb-tsA 58获得的间充质和成釉器上皮细胞 转基因小鼠（ImmortoMouse）将表现为永生化细胞， 在干扰素存在下维持在培养物中， 诱导分化为成牙本质细胞和成釉细胞， 随后形成矿化致密层和釉质细胞外 通过改变培养条件，分别对基质进行了培养。 如果我们的假设是正确的，这项研究将代表一个重大的 牙科领域的突破。 这些细胞可以在高浓度的 数量和用于多项研究，如确定 组织特异性基因的推定调控区;分离和 表征转录因子;分离和表征其他 细胞外基质成分，并确定其作用， 生物矿化，并确定生长因子，激素， 等，从而提供了一个系统，以阐明机制，支配 参与牙齿发育的分子程序。 另外这些 细胞系可用于测试水泥、陶瓷等的毒性， 生物相容性 此外，可以获得类似的细胞系， 其它颅面组织如成牙骨质细胞，唾液腺， 牙周韧带，腭，牙龈和成骨细胞，从而减少 用于这些类型研究的动物数量相当多。

Availability of cell lines has been central to the study of developmental, cellular and molecular biology. Several investigators have attempted to place odontogenic cells (ameloblast, odontoblast, cementoblast) in culture with several degrees of success, and although some have attempted to produced immortalized cell lines derived from pulpal cells (Sato and Ozawa, 1975; Kasugai et al. 1988) and enamel organ epithelial cells (Chen et al, 1992), none of these cells lines have been demonstrated to be capable of producing a mineralized matrix. A transgenic mice harboring the SC40 strain tsA58 early region coding sequences under the control of the mouse major histocompatibility complex H-2Kb class I promoter is now available from Charles River. This promoter is active at various levels in different tissues of the body but in the presence of interferon (IFNs) can be induced to higher levels in almost all cells. These transgenic mice (H-2Kb-tsA58) have the potential of producing cell lines derived from any different tissues, which can behave like immortal cell while in the presence of gamma-IFN at permissive temperatures and then allowed to differentiate by removing the inducer and maintained at non-permissive temperatures (Jan et al. 1991). Cell lines derived from skin fibroblasts (Jat el al, 1991), osteoclast cells (Chambers et al, 1993), colon and small intestine epithelial cells (Whitehead et al, 1993) and astrocyte cells (Groves et al, 1993) using H-2Kb-tsA58 transgenic mice have been described. In this study, we propose to test the hypotheses that dental papillae mesenchyme and enamel organ epithelial cells obtained from H-2Kb-tsA58 transgenic mice (ImmortoMouse) will behave as immortalized cells while maintained in culture in the presence of interferon and they can be induced to differentiate into odontoblast and ameloblast cells with the subsequent formation of a mineralized dentime and enamel extracellular matrix respectively by changing the culture conditions. If our hypothesis is correct, this study will represent a major breakthrough in the dental field. These cells can then be grown in high quantities and used for multiple studies such as determination of putative regulatory regions for tissues specific genes; to isolate and characterize transcription factors; to isolate and characterize other extracellular matrix components and to determine their role in biomineralization and to determine the role of growth factors, hormones, etc, thus providing a system to elucidate the mechanism that govern the molecular programs involved in tooth development. In addition, these cells lines can be used to test cements, ceramics, etc. for toxicity and biocompatibility. Furthermore, similar cell lines can be obtained for other craniofacial tissues such as cementoblast, salivary glands, periodontal ligament, palate, gingiva and osteoblast thus reducing considerably the number of animals used for these type of studies.