The establishment of methods for reproduction of functional teeth by use of long-term culture

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The purposes 1 and 2 of this study was "making an index about multipotent-rerated genes in cranial neural crest cells (NCCs) by the elucidating gene expression during tooth development" and "establishing a method to produce multipotenial cells by use of the index mentioned above", respectively. However, the amount of RNA of NCCs in the histological section was too small to make the index mentioned above. Therefore, I had stopped the experiments. Therefore, we mainly carried out the studies for "establishing methods reproducing the tooth, periodontal tissues and other craniofacial organs by use of rat whole embryo culture (WEC)", i.e., the purposes 3.During above experimens, we focused on the differences between developmental processes of tooth and pituitary, and carried out the studies. We got new findings as follows. 1. The ectoderm-endoderm boundaries and midbrain-hindbrain NCCs contributes to tooth initiation. 2. The non-neuronal anterior neural ridge (ANR) of ectoderm-endoderm boundaries gives rise to ACTH-producing cells. 3. The prechordal plate (PrP) intrudes itself in ANR and neural plate, contributes to prechordal mesenchyme and intraforebrain mesenchyme, and gives rise to endocrine cells in pituitary. 4. The site-specific distribution of PrP-derived cells is required to the differentiation of the tooth, adenohypophysis and hypothalamus. 5. The many developmental defects occur in PrP-ablation mice similarly to in Shh K.O. mice. We established the niche for reproducing the cells producing pituitary hormones, e.g., ACTH,αGSU,αMsh, TSHβ and LHβ, in the above results 3 by the long-term maxillofacial organ culture of Rathck's pouch accompanied with diencephalon. 6. We show the domain that is important for reproduction of tooth, jaw in a development process of a chin of birds. 7. We are establishing the reproduction methods to craniofacial organ, including hypothalamic nucleus relating to feeding behavior, by use of WEC.