Nuclear organization in differentiating oligodendrocytes
Nuclear organization in differentiating oligodendrocytes
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DOI：
10.1242/jcs.00103
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发表时间：
2002-11-01
影响因子：
4
通讯作者：
Armstrong, RC
中科院分区：
文献类型：
--
作者：
Nielsen, JA;Hudson, LD;Armstrong, RC
许多研究表明，核内染色质和蛋白质的三维组织有助于基因表达的调控。我们在原代细胞培养系统中测试了这种核组织模型的多个方面。少突胶质细胞谱系细胞进行了检查，以便于分析核组织相对于一个高度表达的组织特异性基因，蛋白脂质蛋白（PLP），它表现出转录上调从未成熟的祖细胞阶段分化到成熟的少突胶质细胞阶段。从新生雄性啮齿动物的脑中分离少突胶质细胞谱系细胞，并通过培养条件控制从少突胶质细胞祖细胞向成熟少突胶质细胞的分化。基因组原位杂交用于检测每个间期核内X连锁PLP基因的单拷贝。PLP基因并非随机分布在细胞核内，而是始终与祖细胞和分化的少突胶质细胞的核外周相关。PLP和第二个同时上调的基因，髓鞘碱性蛋白（MBP）基因，在空间上分离的祖细胞和分化的少突胶质细胞。PLP基因在分化少突胶质细胞中的转录活性增加与SC 35剪接因子的局部积累相对应。分化并没有改变PLP基因与髓鞘转录因子1（Myt 1）结合PLP启动子的结构域的关联频率。除了我们与PLP基因相关的具体发现之外，从原代少突胶质细胞谱系细胞获得的这些数据支持核组织模型，其中（1）核蛋白和基因可以在核内表现出特定的分布模式，以及（2）组织特异性基因的激活与局部蛋白分布的变化相关，而不是协调调节基因的空间聚集。这种核组织对于控制正常细胞发育的复杂核酸-蛋白质相互作用可能是至关重要的，并且可能是转化细胞中细胞分化和基因表达的异常调节的重要因素。
Many studies have suggested that the 3D organization of chromatin and proteins within the nucleus contributes to the regulation of gene expression. We tested multiple aspects of this nuclear organization model within a primary cell culture system. Oligodendrocyte lineage cells were examined to facilitate analysis of nuclear organization relative to a highly expressed tissue-specific gene, proteolipid protein (PLP), which exhibits transcriptional upregulation during differentiation from the immature progenitor stage to the mature oligodendrocyte stage. Oligodendrocyte lineage cells were isolated from brains of neonatal male rodents, and differentiation from oligodendrocyte progenitors to mature oligodendrocytes was controlled with culture conditions. Genomic in situ hybridization was used to detect the single copy of the X-linked PLP gene within each interphase nucleus. The PLP gene was not randomly distributed within the nucleus, but was consistently associated with the nuclear periphery in both progenitors and differentiated oligodendrocytes. PLP and a second simultaneously upregulated gene, the myelin basic protein (MBP) gene, were spatially separated in both progenitors and differentiated oligodendrocytes. Increased transcriptional activity of the PLP gene in differentiated oligodendrocytes corresponded with local accumulation of SC35 splicing factors. Differentiation did not alter the frequency of association of the PLP gene with domains of myelin transcription factor 1 (Myt1), which binds the PLP promoter. In addition to our specific findings related to the PLP gene, these data obtained from primary oligodendrocyte lineage cells support a nuclear organization model in which (1) nuclear proteins and genes can exhibit specific patterns of distribution within nuclei, and (2) activation of tissue-specific genes is associated with changes in local protein distribution rather than spatial clustering of coordinately regulated genes. This nuclear organization may be critical for complex nucleic-acid-protein interactions controlling normal cell development, and may be an important factor in aberrant regulation of cell differentiation and gene expression in transformed cells.