Expression of the bZIP transcription factor gene Nrl in the developing nervous system.
Expression of the bZIP transcription factor gene Nrl in the developing nervous system.
复制标题
bZIP 转录因子基因 Nrl 在发育中的神经系统中的表达。
作者：
Q R Liu;X. Ji;M. Breitman;P. Hitchcock;A. Swaroop
bZIP 转录因子 Maf/Nrl 亚家族的蛋白质参与组织特异性基因表达的调节。 Nrl 基因最初是从消减的视网膜文库中鉴定出来的，在成人视网膜的所有细胞层中表达，包括感光细胞。 Nrl 蛋白与 Maf 蛋白具有高度序列同源性，与 AP-1 样序列元件结合，并且在光感受器中似乎参与调节视紫红质的表达。在本研究中，我们利用原位杂交和 RT-PCR 研究了 Nrl 在发育中和成年小鼠中的表达。我们证明，从胚胎日开始，12.5 Nrl 在整个发育中的中枢和周围神经系统中表达，鼻上皮除外。杂交的空间模式表明 Nrl 在有丝分裂后、分化的神经元、发育中的头部间充质和晶状体中转录。 Nrl 表达在出生后在大脑中下调，并且在成人中仅限于新皮质和脑干。然而，高水平的 Nrl 转录本仍然存在于成熟的光感受器和其他视网膜神经元中。我们的研究表明 Nrl 蛋白在神经元分化和成人视网膜成熟神经元中发挥作用。
Proteins of the Maf/Nrl subfamily of bZIP transcription factors are involved in the regulation of tissue-specific gene expression. The Nrl gene, initially identified from a subtracted retinal library, is expressed in all cell layers of the adult retina, including photoreceptors. The Nrl protein has high sequence homology with Maf proteins, binds to an AP-1 like sequence element, and in photoreceptors appears to be involved in regulating the expression of rhodopsin. In the present study, we investigated the expression of Nrl in the developing and adult mouse using in situ hybridization and RT-PCR. We demonstrate that beginning at embryonic day 12.5 Nrl is expressed throughout the developing central and peripheral nervous system, with the exception of the nasal epithelium. The spatial pattern of hybridization suggests that Nrl is transcribed in post-mitotic, differentiating neurons, the developing cephalic mesenchyme and lens. Nrl expression is downregulated postnatally in the brain, and becomes restricted to neocortex and brainstem in the adult. High levels of Nrl transcripts, however, persist in the mature photoreceptors and other retinal neurons. Our studies suggest a role for the Nrl protein in neuronal differentiation and in mature neurons of the adult retina.