Purα is essential for postnatal brain development and developmentally coupled cellular proliferation as revealed by genetic inactivation in the mouse
Purα is essential for postnatal brain development and developmentally coupled cellular proliferation as revealed by genetic inactivation in the mouse
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DOI：
10.1128/mcb.23.19.6857-6875.2003
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发表时间：
2003-10-01
影响因子：
5.3
通讯作者：
Gordon, J
中科院分区：
文献类型：
--
作者：
Khalili, K;Del Valle, L;Gordon, J
单链DNA和RNA结合蛋白Puralpha参与了许多生物学过程，包括控制多个基因的转录、启动DNA复制以及RNA转运和翻译。PURA基因的缺失在急性髓细胞白血病中是常见的。在两个等位基因中靶向破坏PURA基因的小鼠在出生时表现正常，但在2周龄时，它们出现神经系统问题，表现为严重震颤和自发性癫痫发作，并在4周内死亡。与年龄匹配的+/+同窝出生小鼠相比，PURA（-/-）小鼠海马和小脑区域的神经元数量严重减少，死亡时这些区域的分层异常。DNA复制的蛋白标记物MCM 7的免疫组织化学分析揭示了PURA（-/-）小鼠中这些区域中缺乏前体细胞的增殖。在PURA（-/-）小鼠的几种其他组织中，包括髓系组织，增殖水平也不存在或较低，而PURA（-/-）小鼠的增殖水平居中。脑切片的评价表明，少突胶质细胞和星形胶质细胞中髓鞘和胶质细胞酸性蛋白标记分别减少，表明这些细胞的病理发展。在出生后第5天，小脑发育的关键时间，Pura和Cdk 5都在PUR+/+小鼠的浦肯野细胞的体和树突的峰值水平，但都没有在PURA-1-小鼠的树突。Puralpha和Cdk 5可以从PURA（+/+）小鼠的脑裂解物中共免疫沉淀。免疫组织化学研究表明，浦肯野细胞层的树突和海马突触形成的磷酸化和非磷酸化神经丝的水平显着减少。总体结果与Puralpha在特定细胞类型中发育定时DNA复制中的作用一致，并且还指出了在神经元树突中区室化RNA运输和翻译中的新出现的作用。
The single-stranded DNA- and RNA-binding protein, Puralpha, has been implicated in many biological processes, including control of transcription of multiple genes, initiation of DNA replication, and RNA transport and translation. Deletions of the PURA gene are frequent in acute myeloid leukemia. Mice with targeted disruption of the PURA gene in both alleles appear normal at birth, but at 2 weeks of age, they develop neurological problems manifest by severe tremor and spontaneous seizures and they die by 4 weeks. There are severely lower numbers of neurons in regions of the hippocampus and cerebellum of PURA(-/-) mice versus those of age-matched +/+ littermates, and lamination of these regions is aberrant at time of death. Immunohistochemical analysis of MCM7, a protein marker for DNA replication, reveals a lack of proliferation of precursor cells in these regions in the PURA(-/-) mice. Levels of proliferation were also absent or low in several other tissues of the PURA(-/-) mice, including those of myeloid lineage, whereas those of PURA(-/-) mice were intermediate. Evaluation of brain sections indicates a reduction in myelin and glial fibrillary acidic protein labeling in oligodendrocytes and astrocytes, respectively, indicating pathological development of these cells. At postnatal day 5, a critical time for cerebellar development, Pura and Cdk5 were both at peak levels in bodies and dendrites of Purkinje cells of PUR+/+ mice, but both were absent in dendrites of PURA-1- mice. Puralpha and Cdk5 can be coimmunoprecipitated from brain lysates of PURA(+/+) mice. Immunohistochemical studies reveal a dramatic reduction in the level of both phosphorylated and nonphosphorylated neurofilaments in dendrites of the Purkinje cell layer and of synapse formation in the hippocampus. Overall results are consistent with a role for Puralpha in developmentally timed DNA replication in specific cell types and also point to a newly emerging role in compartmentalized RNA transport and translation in neuronal dendrites.