Sakakibara S, Nakamura Y, Satoh H, Okano H
Division of Neuroanatomy, Department of Neuroscience, Biomedical Research Center, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan.
J Neurosci. 2001 Oct 15;21(20):8091-107. doi: 10.1523/JNEUROSCI.21-20-08091.2001.
Musashi1 (Msi1) is a mammalian neural RNA-binding protein highly enriched in neural precursor cells that are capable of generating both neurons and glia during embryonic and postnatal CNS development. Here, we identified Musashi2 (Msi2), a novel mammalian RNA-binding protein that exhibits high sequence similarity to Msi1. The Msi2 transcript appeared to be distributed ubiquitously in a wide variety of tissues, consistent with the mRNA distribution of its Xenopus homolog, xrp1. However, the present study revealed cell type-specific and developmentally regulated expression of Msi2 in the mammalian CNS. Interestingly, Msi2 was expressed prominently in precursor cells in the ventricular zone and subventricular zone with the same pattern as Msi1 throughout CNS development. In the postnatal and adult CNS, this concurrent expression of Msi2 and Msi1 was seen in cells of the astrocyte lineage, including ependymal cells, a possible source for postnatal CNS stem cells. During neurogenesis, the expression of both Msi2 and Msi1 was lost in most postmitotic neurons, whereas Msi2 expression persisted in a subset of neuronal lineage cells, such as parvalbumin-containing GABA neurons in the neocortex and neurons in several nuclei of the basal ganglia. Msi2 may have a unique role that is required for the generation and/or maintenance of specific neuronal lineages. Furthermore, in vitro studies showed that Msi2 and Msi1 have similar RNA-binding specificity. These two RNA-binding proteins may exert common functions in neural precursor cells by regulating gene expression at the post-transcriptional level.
Musashi1（Msi1）是一种哺乳动物神经RNA结合蛋白，在神经前体细胞中高度富集，这些细胞在胚胎期和出生后中枢神经系统（CNS）发育过程中能够产生神经元和神经胶质细胞。在此，我们鉴定出了Musashi2（Msi2），一种与Msi1具有高度序列相似性的新型哺乳动物RNA结合蛋白。Msi2转录本似乎广泛分布于多种组织中，这与其非洲爪蟾同源物xrp1的mRNA分布一致。然而，本研究揭示了Msi2在哺乳动物CNS中的细胞类型特异性和发育调控表达。有趣的是，在整个CNS发育过程中，Msi2在脑室区和室下区的前体细胞中显著表达，其模式与Msi1相同。在出生后和成年CNS中，Msi2和Msi1的这种共表达见于星形胶质细胞系的细胞，包括室管膜细胞，后者可能是出生后CNS干细胞的一个来源。在神经发生过程中，Msi2和Msi1在大多数有丝分裂后神经元中表达缺失，而Msi2表达在神经元谱系细胞的一个子集中持续存在，例如新皮质中含小白蛋白的GABA能神经元和基底神经节几个核中的神经元。Msi2可能在特定神经元谱系的产生和/或维持中具有独特作用。此外，体外研究表明Msi2和Msi1具有相似的RNA结合特异性。这两种RNA结合蛋白可能通过在转录后水平调节基因表达，在神经前体细胞中发挥共同功能。
