Sakakibara S, Okano H
Department of Neuroanatomy, Biomedical Research Center, Osaka University Medical School, Suita, Osaka 565, Japan.
J Neurosci. 1997 Nov 1;17(21):8300-12. doi: 10.1523/JNEUROSCI.17-21-08300.1997.
There is an increasing interest in the role of RNA-binding proteins during neural development. Mouse-Musashi-1 (m-Msi-1) is a mouse neural RNA-binding protein with sequence similarity to Drosophila musashi (d-msi), which is essential for neural development. m-Msi-1 is highly enriched in neural precursor cells that are capable of generating both neurons and glia during embryonic CNS development. The present study characterized m-Msi-1-expressing cells in the postnatal and adult CNS. Postnatally, m-Msi-1 was expressed in proliferative neuronal precursors in the external granule cell layer of the cerebellum and in the anterior corner of the subventricular zone of the lateral ventricles. In gliogenesis, the persistent expression of m-Msi-1 was observed in cells of the astrocyte lineage ranging from proliferative glial precursors in the subventricular zone (SVZ) to differentiated astrocytes in the parenchyma. In addition, we showed that m-Msi-1 was still expressed in proliferating cells in the adult SVZ, which may contain neural precursor or stem cells. Another neural RNA-binding protein Hu (the mammalian homolog of a Drosophila neuronal RNA-binding protein Elav) was present in postmitotic neurons throughout the development of the CNS, and its pattern of expression was compared with that of m-Msi-1. These observations imply that these two RNA-binding proteins may be involved in the development of neurons and glia by regulating gene expression at the post-transcriptional level.
人们对RNA结合蛋白在神经发育过程中的作用越来越感兴趣。小鼠Musashi-1（m-Msi-1）是一种小鼠神经RNA结合蛋白，其序列与果蝇Musashi（d-msi）相似，而d-msi对神经发育至关重要。m-Msi-1在胚胎中枢神经系统发育过程中，在能够产生神经元和神经胶质细胞的神经前体细胞中高度富集。本研究对出生后及成年中枢神经系统中表达m-Msi-1的细胞进行了特征描述。出生后，m-Msi-1在小脑外颗粒细胞层和侧脑室室管膜下区前角的增殖性神经元前体细胞中表达。在神经胶质生成过程中，观察到m-Msi-1在星形胶质细胞谱系的细胞中持续表达，范围从室管膜下区（SVZ）的增殖性神经胶质前体细胞到实质中的分化星形胶质细胞。此外，我们发现m-Msi-1在成年SVZ的增殖细胞中仍有表达，这些增殖细胞可能包含神经前体细胞或干细胞。另一种神经RNA结合蛋白Hu（果蝇神经元RNA结合蛋白Elav的哺乳动物同源物）在中枢神经系统发育的整个过程中都存在于有丝分裂后的神经元中，并将其表达模式与m-Msi-1的表达模式进行了比较。这些观察结果表明，这两种RNA结合蛋白可能通过在转录后水平调节基因表达，参与神经元和神经胶质细胞的发育。
