Goulding M D, Lumsden A, Gruss P
Department of Molecular Cell Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
Development. 1993 Mar;117(3):1001-16. doi: 10.1242/dev.117.3.1001.
Members of the paired box (Pax) gene family are expressed in discrete regions of the developing central nervous system, suggesting a role in neural patterning. In this study, we describe the isolation of the chicken homologues of Pax-3 and Pax-6. Both genes are very highly conserved and share extensive homology with the mouse Pax-3 and Pax-6 genes. Pax-3 is expressed in the primitive streak and in two bands of cells at the lateral extremity of the neural plate. In the spinal cord, Pax-6 is expressed later than Pax-3 with the first detectable expression preceding closure of the neural tube. When the neural tube closes, transcripts of both genes become dorsoventrally restricted in the undifferentiated mitotic neuroepithelium. We show that the removal of the notochord, or implantation of an additional notochord, dramatically alter the dorsoventral (DV) expression patterns of Pax-3 and Pax-6. These manipulations suggest that signals from the notochord and floor plate regulate the establishment of the dorsoventrally restricted expression domains of Pax-3 and Pax-6 in the spinal cord. The rapid changes to Pax gene expression that occur in neural progenitor cells following the grafting of an ectopic notochord suggest that changes to Pax gene expression are an early effect of the notochord on spinal cord patterning.
成对盒（Pax）基因家族的成员在发育中的中枢神经系统的离散区域表达，这表明它们在神经模式形成中发挥作用。在本研究中，我们描述了鸡Pax-3和Pax-6同源物的分离。这两个基因都高度保守，并且与小鼠的Pax-3和Pax-6基因具有广泛的同源性。Pax-3在原条以及神经板外侧末端的两条细胞带中表达。在脊髓中，Pax-6的表达晚于Pax-3，在神经管闭合之前首次检测到表达。当神经管闭合时，这两个基因的转录本在未分化的有丝分裂神经上皮中沿背腹方向受到限制。我们发现，去除脊索或植入额外的脊索会显著改变Pax-3和Pax-6的背腹（DV）表达模式。这些操作表明，来自脊索和底板的信号调节脊髓中Pax-3和Pax-6背腹方向受限表达域的建立。异位脊索移植后神经祖细胞中Pax基因表达的快速变化表明，Pax基因表达的变化是脊索对脊髓模式形成的早期影响。
