Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles 90095, USA.
Dev Neurobiol. 2013 Feb;73(2):152-67. doi: 10.1002/dneu.22049. Epub 2012 Sep 27.
To analyze somatosensory neuron diversity in larval zebrafish, we identified several enhancers from the zebrafish and pufferfish genomes and used them to create five new reporter transgenes. Sequential deletions of three of these enhancers identified small sequence elements sufficient to drive expression in zebrafish trigeminal and Rohon-Beard (RB) neurons. One of these reporters, using the Fru.p2x3-2 enhancer, highlighted a somatosensory neuron subtype that expressed both the p2rx3a and pkcα genes. Comparison with a previously described trpA1b reporter revealed that it highlighted the same neurons as the Fru.p2x3-2 reporter. To determine whether neurons of this subtype possess characteristic peripheral branching morphologies or central axon projection patterns, we analyzed the morphology of single neurons. Surprisingly, although these analyses revealed diversity in peripheral axon branching and central axon projection, PKCα/p2rx3a/trpA1b-expressing RB cells did not possess obvious characteristic morphological features, suggesting that even within this molecularly defined subtype, individual neurons may possess distinct properties. The new transgenes created in this study will be powerful tools for further characterizing the molecular, morphological, and developmental diversity of larval somatosensory neurons.
为了分析幼虫斑马鱼的感觉神经元多样性，我们从斑马鱼和河豚基因组中鉴定了几个增强子，并使用它们创建了五个新的报告基因转基因。对其中三个增强子进行的顺序缺失确定了小的序列元件，足以驱动在斑马鱼三叉神经和 Rohon-Beard (RB) 神经元中的表达。这些报告基因中的一个，使用 Fru.p2x3-2 增强子，突出显示了一种表达 p2rx3a 和 pkcα 基因的感觉神经元亚型。与之前描述的 trpA1b 报告基因的比较表明，它突出显示了与 Fru.p2x3-2 报告基因相同的神经元。为了确定这个亚型的神经元是否具有特征性的外周分支形态或中枢轴突投射模式，我们分析了单个神经元的形态。令人惊讶的是，尽管这些分析显示了外周轴突分支和中枢轴突投射的多样性，但 PKCα/p2rx3a/trpA1b 表达的 RB 细胞没有明显的特征形态特征，这表明即使在这个分子定义的亚型内，单个神经元也可能具有不同的特性。本研究中创建的新转基因将成为进一步表征幼虫感觉神经元的分子、形态和发育多样性的有力工具。
