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Tissue patterning mechanisms of facial prominences in chicken embryo

鸡胚面部突起的组织模式机制

基本信息

批准号：
13672146
负责人：
KAWAKAMI Masayoshi
金额：
$ 2.24万
依托单位：
Nara Medical University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13672146/
关键词：
chick embryo frontonasal mass cleft lip Msx-1 craniofacial epithelial facial primodial chondrogenesis Msx-1 embryo limb bud 顔面骨格軟骨形成

项目摘要

Local patterning events occur within the frontonasal mass, one of the facial prominences that surrounds the embryonic oral cavity. In the chicken embryo, the upper beak is primarily formed by the frontonasal mass, the prominence that lies between the nasal slits. In the present study we dissociate mesenchyme from the lateral and central thirds of the frontonasal mass and compare the ability to form a single cartilage rod. We find that central third cell pellets combined with facial epithelium have a tendency to form a straight cartilage rod whereas the cells from the lateral third produce more branched outgrowths. In the reconstituted cell pellets with lateral and central cells mixed together, the central cells aggregate in the cartilage condensations while lateral cells are distributed throughout the graft. The central cell pellets contain greater numbers of potential chondrogenic cells than lateral cell pellets.To see whether medio-lateral patterning is re-established in the cell pellets, we used Msx-2 as a marker for the lateral mesenchyme at stage 24. Central cell pellet recombinations do not express the gene or turn on bilateral expression. Grafts of lateral cells maintain and up-regulate Msx-2 expression 48 hours after grafting, but are not able to establish bilateral symmetry. The cell pellets that are mixtures of central and lateral third mesenchyme often express three patches of Msx-2 transcripts. Thus the central region of the frontonasal mass probably contains the majority of prechondrogenic cells at stage 24 and these cells have a tendency to segregate from the surrounding non-chondrogenic mesenchyme. Msx-2 may help to set up the differences between central and lateral mesenchyme prior to cell differentiation.

局部图案化事件发生在额鼻部肿块内，额鼻部肿块是包围胚胎口腔的面部隆起之一。在鸡胚中，上喙主要是由位于鼻缝之间的额鼻团形成的。在本研究中，我们将间充质从额鼻肿块的外侧和中央分离出来，并比较形成单个软骨棒的能力。我们发现，中央第三细胞颗粒与面部上皮结合有形成直软骨棒的趋势，而来自外侧第三细胞颗粒的细胞产生更多的分枝突起。在侧细胞和中央细胞混合在一起的重组细胞小球中，中央细胞聚集在软骨凝聚体中，而侧细胞分布在移植物的各处。在24期，我们使用MSX-2作为外侧间充质的标记物，以观察细胞颗粒中是否重建了中侧向图案。中央细胞颗粒重组不表达该基因，也不开启双向表达。侧细胞移植后48小时维持并上调MSX-2的表达，但不能建立两侧对称性。细胞颗粒是中央和外侧第三间充质的混合物，通常表达三块MSX-2转录本。因此，在24期，额鼻肿块的中央区域可能包含大多数前软骨细胞，这些细胞有从周围的非软骨细胞间充质分离的趋势。MSX-2可能有助于在细胞分化之前建立中央和外侧间充质之间的差异。