Nural Hikmet Feyza, Todd Farmer W, Mastick Grant S
Department of Biology, University of Nevada, Reno, NV 89557, USA.
Gene Expr Patterns. 2007 Oct;7(8):837-45. doi: 10.1016/j.modgep.2007.07.004. Epub 2007 Aug 7.
Robo1 is a member of the Roundabout (Robo) family of receptors for the Slit axon guidance cues. In mice (and humans), the Robo1 locus has alternative promoters producing two transcript isoforms, Robo1 and Dutt1. These isoforms have unique 5' termini, predicted to encode distinct N-terminal amino acids, but share the rest of their 3' exons. To determine the spatial expression of the Robo1 and Dutt1 isoforms, we generated isoform-specific RNA probes, and carried out in situ hybridization on E10.5 mouse embryos, the stage in early neuron differentiation when many major axon pathways are established. The two isoforms had distinct expression patterns that partially overlapped. Dutt1 was the predominant isoform, with widespread expression in regions of post-mitotic neurons and neuroepithelial cells. The Robo1 isoform had a distinct expression pattern restricted to subsets of neurons, many of which were Dutt1-negative. Dutt1 was the main isoform expressed in spinal cord commissural neurons. For both probes, the main hybridization signal was limited to two spots in the nuclei of individual cells. This study shows distinct expression patterns for the Dutt1 and Robo1 alternative promoters in the embryonic nervous system.
Robo1是Slit轴突导向信号受体的Roundabout（Robo）家族成员。在小鼠（和人类）中，Robo1基因座有多个可选择的启动子，产生两种转录异构体，即Robo1和Dutt1。这些异构体具有独特的5'末端，预计编码不同的N端氨基酸，但共享其余的3'外显子。为了确定Robo1和Dutt1异构体的空间表达，我们制备了异构体特异性RNA探针，并对E10.5小鼠胚胎进行原位杂交，这是早期神经元分化阶段，此时许多主要轴突通路已建立。这两种异构体具有部分重叠的不同表达模式。Dutt1是主要异构体，在有丝分裂后神经元和神经上皮细胞区域广泛表达。Robo1异构体具有独特的表达模式，仅限于神经元亚群，其中许多是Dutt1阴性。Dutt1是脊髓连合神经元中表达的主要异构体。对于这两种探针，主要杂交信号仅限于单个细胞核中的两个点。这项研究显示了Dutt1和Robo1在胚胎神经系统中可选择启动子的不同表达模式。
