Schwarz M, Alvarez-Bolado G, Dressler G, Urbánek P, Busslinger M, Gruss P
Max Planck Institute of Biophysical Chemistry, Am Fassberg, 37077, Göttingen, Germany.
Mech Dev. 1999 Apr;82(1-2):29-39. doi: 10.1016/s0925-4773(99)00005-2.
The nested expression patterns of the paired-box containing transcription factors Pax2/5 and Pax6 demarcate the midbrain and forebrain primordium at the neural plate stage. We demonstrate that, in Pax2/5 deficient mice, the mesencephalon/metencephalon primordium is completely missing, resulting in a fusion of the forebrain to the hindbrain. Morphologically, in the alar plate the deletion is characterized by the substitution of the tectum (dorsal midbrain) and cerebellum (dorsal metencephalon) by the caudal diencephalon and in the basal plate by the replacement of the midbrain tegmentum by the ventral metencephalon (pons). Molecularly, the loss of the tectum is demonstrated by an expanded expression of Pax6, (the molecular determinant of posterior commissure), and a rostral shift of the territory of expression of Gbx2 and Otp (markers for the pons), towards the caudal diencephalon. Our results suggest that an intact territory of expression of Pax2/5 in the neural plate, nested between the rostral and caudal territories of expression of Pax6, is necessary for defining the midbrain vesicle.
成对盒转录因子Pax2/5和Pax6的嵌套表达模式在神经板阶段界定了中脑和前脑原基。我们证明，在Pax2/5基因缺失的小鼠中，中脑/后脑原基完全缺失，导致前脑与后脑融合。形态学上，在翼板中，这种缺失的特征是尾侧间脑替代了顶盖（中脑背侧）和小脑（后脑背侧），在基板中，中脑被盖被腹侧后脑（脑桥）替代。分子水平上，Pax6（后连合的分子决定因素）表达的扩展以及Gbx2和Otp（脑桥标记物）表达区域向尾侧间脑的 Rostral 移位表明顶盖缺失。我们的结果表明，神经板中Pax2/5的完整表达区域，嵌套在Pax6的头侧和尾侧表达区域之间，对于定义中脑泡是必要的。
