Andermann Peter, Ungos Josette, Raible David W
Department of Biological Structure, University of Washington, Seattle 98195-7420, USA.
Dev Biol. 2002 Nov 1;251(1):45-58. doi: 10.1006/dbio.2002.0820.
Cells delaminate from epithelial placodes to form sensory ganglia in the vertebrate head. We describe the formation of cranial neurogenic placodes in the zebrafish, Danio rerio, using bHLH transcription factors as molecular markers. A single neurogenin gene, neurogenin1 (ngn1), is required for the development of all zebrafish cranial ganglia, which contrasts with other described vertebrates. Expression of ngn1 delineates zebrafish ganglionic placodes, including trigeminal, lateral line, and epibranchial placodes. In addition, ngn1 is expressed in a subset of cells within the otic vesicle that will delaminate to form the octaval (statoacoustic) ganglion. The trigeminal placode is the first to differentiate, and forms just lateral and adjacent to the neural crest. Expression of ngn1 is transient and prefigures expression of a related bHLH transcription factor, neuroD. Interfering with ngn1 function using a specific antisense morpholino oligonucleotide blocks differentiation of all cranial ganglia but not associated glial cells. Lateral line sensory neuromasts develop independently of ngn1 function, suggesting that two derivatives of lateral line placodes, ganglia and migrating primordia, are under separate genetic control.
在脊椎动物头部，细胞从上皮基板脱离以形成感觉神经节。我们利用bHLH转录因子作为分子标记，描述了斑马鱼（Danio rerio）中颅神经源性基板的形成。单个神经生成素基因，即神经生成素1（ngn1），是所有斑马鱼颅神经节发育所必需的，这与其他已描述的脊椎动物形成对比。ngn1的表达勾勒出斑马鱼的神经节基板，包括三叉神经、侧线和鳃上基板。此外，ngn1在耳泡内的一部分细胞中表达，这些细胞将脱离以形成八分体（ statoacoustic）神经节。三叉神经基板是第一个分化的，形成于神经嵴的外侧并与之相邻。ngn1的表达是短暂的，并预示着相关bHLH转录因子neuroD的表达。使用特定的反义吗啉代寡核苷酸干扰ngn1的功能会阻断所有颅神经节的分化，但不会影响相关的神经胶质细胞。侧线感觉神经丘独立于ngn1的功能发育，这表明侧线基板的两种衍生物，神经节和迁移的原基，受不同的基因控制。
