Graham A, Francis-West P, Brickell P, Lumsden A
MRC Brain Development Programme, UMDS, Guys Hospital, London, UK.
Nature. 1994 Dec 15;372(6507):684-6. doi: 10.1038/372684a0.
The pattern of skeletal structures and muscles in the branchial region of the head is profoundly influenced by the neural crest, whose cells arise at discrete segmental levels of the chick hindbrain: specifically, rhombomeres (r)1+2, r4 and r6, whereas r3 and r5 are crest-depleted. We have demonstrated that an interaction between even-numbered rhombomeres and r3/r5 effects this depletion of neural crest, resulting in the sculpting of discrete migratory streams of neural crest. This mechanism acts through increased expression of msx2 and the induction of apoptosis in dorsal cells of r3 and r5 (ref. 3) (Fig. 1A). Here we demonstrate that the signalling molecule Bmp4 is expressed in r3 and r5 and is dependent on the neighbouring rhombomeres. Addition of recombinant BMP4 protein to explant cultures of r3 or r5, which produce neural crest when isolated from their neighbouring rhombomeres, upregulates msx2 and reinstates apoptosis in the neural crest population.
头部鳃区的骨骼结构和肌肉模式受到神经嵴的深刻影响，神经嵴细胞起源于鸡胚后脑的离散节段水平：具体来说，是菱脑节（r）1+2、r4和r6，而r3和r5则缺乏神经嵴细胞。我们已经证明，偶数菱脑节与r3/r5之间的相互作用导致了神经嵴的这种缺失，从而形成了离散的神经嵴迁移流。该机制通过msx2表达的增加以及r3和r5背侧细胞中凋亡的诱导来发挥作用（参考文献3）（图1A）。在这里，我们证明信号分子Bmp4在r3和r5中表达，并且依赖于相邻的菱脑节。将重组BMP4蛋白添加到从相邻菱脑节分离后能产生神经嵴的r3或r5外植体培养物中，会上调msx2并恢复神经嵴群体中的细胞凋亡。
