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研究発表を行った学会；
・第４０回日本発生生物学会・第５９回日本細胞生物学会　合同大会、2007年 5月28~30日(福岡)

タイトル；Morphological features of the apical surface of the neuroepithelium.
発表者；　畠山　淳　氏
　　　（熊本大学　発生医学研究センター　形態形成分野）
Abstract；
The developing central nervous system (CNS) is partitioned into many compartments by the boundary cells. Some of these boundaries have been shown to serve as organizing centers that regulate patterning of the neighboring compartments by secreting signaling molecules. For example, the zona limitans intrathalamica (ZLI) which demarcates the prethalamus and thalamus regulates neuronal specification of both compartments by secreting Sonic hedgehog (Shh). The floor plate directs the dorsoventral patterning of the spinal cord by secreting Shh. These boundaries are comprised by characteristic neuroepithelial or radial glial cells that have different properties from the adjoining non-boundary cells. In the boundaries, neurogenesis does not take place or is delayed and the cells proliferate very slowly.
To understand the development and functions of the boundaries in detail, we have conducted a series of morphological and ultrastructural studies of them. The apical surface of boundary cells, such as the ZLI, floor plate and roof plate, is smooth and wide (3-5nm on diameter) and they have monocilia. By contrast, the non-boundary cells have rough and relatively small (1-2nm on diameter) apical surface. While they also have monocilia, those are shorter than those of the boundaries and hidden in the rough surface. The monocilium of the boundary cell is composed of 9+0 microtubules, which is same as the nodal cilia, raising a possibility that they are motile and could generate liquid flow. Furthermore, there are often seen many small membranous vesicles upon the apical surface of the floor plate, which is also a similar situation described for the node. We are currently investigating whether these features of the boundary cells indeed contribute to their roles in the patterning of the developing CNS.