Genes transcribed at diverse rates have a similar conformation in chromatin.
Genes transcribed at diverse rates have a similar conformation in chromatin.
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以不同速率转录的基因在染色质中具有相似的构象。
DOI：
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发表时间：
1977
影响因子：
11.1
通讯作者：
R. Axel
中科院分区：
文献类型：
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作者：
A. Garel;M. Zolan;R. Axel
我们分析了用胰DNA酶I（脱氧核糖核酸3 '-腺苷酸水解酶; EC 3.1.4.6）处理输卵管核后产生的DNA，以及特定mRNA序列的cDNA拷贝，以研究染色质中转录活性基因的结构和组织。在这份报告中，我们研究了三个类的基因在输卵管中的转录在显着不同的速率消化的动力学。我们的研究结果表明，卵清蛋白基因似乎是由染色质蛋白以这样一种方式组织起来的，即它们对DNA酶I的消化非常敏感。这种敏感性在肝脏中没有观察到，肝脏是这些基因转录惰性的组织。此外，输卵管中的转录失活的珠蛋白基因对核酸酶攻击不选择性敏感，并且在该组织中的卵清蛋白基因中消化慢5倍。此外，我们还研究了一个复杂的基因子集的可访问性，这些基因很少在mRNA中表达，并且可能以低于卵清蛋白基因的频率数量级转录。这些序列与卵清蛋白基因的可及性的比较表明，这两个基因子集被DNA酶I以相似的速率识别和切割。这些结果表明，特定基因的活性构象的维持并不反映这些基因的聚合酶分布。因此，这种活性构象并不局限于积极参与转录过程的序列，并且可以反映代表给定细胞类型的转录潜力的基因组亚群的结构。
We have analyzed the DNA generated upon treatment of oviduct nuclei with pancreatic DNase I (deoxyribonucleate 3'-oligonucleotidohydrolase; EC 3.1.4.6), with cDNA copies of specific mRNA sequences to study the structure and organization of transcriptionally active genes in chromatin. In this report we examine the kinetics of digestion of three classes of genes in the oviduct which are transcribed at significantly different rates. Our results indicate that the ovalbumin genes appear to be organized by chromatin proteins in such a way that they are rendered exceedingly sensitive to digestion by DNase I. This sensitivity is not observed in the liver, a tissue in which these genes are transcriptionally inert. Furthermore, the transcriptionally inactive globin genes in the oviduct are not selectively sensitive to nuclease attack and are digested 5 times more slowly in the ovalbumin genes in this tissue. In addition, we have examined the accessibility of a complex subset of genes that are rarely represented in the mRNA and are likely to be transcribed at a frequency orders of magnitude below that of the ovalbumin gene. Comparison of the accessibility of these sequences with that of the ovalbumin gene indicates that these two subsets of genes are recognized and cleaved by DNase I at similar rates. These results suggest that the maintenance of an active conformation about specific genes does not reflect the polymerase distribution about these genes. This active conformation is therefore not confined to sequences actively engaged in the transcription process and may reflect the structure about a subpopulation of the genome which represents the transcriptional potential of a given cell type.