THE DNASE-I SENSITIVITY OF XENOPUS-LAEVIS GENES TRANSCRIBED BY RNA POLYMERASE-III
THE DNASE-I SENSITIVITY OF XENOPUS-LAEVIS GENES TRANSCRIBED BY RNA POLYMERASE-III
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DOI：
10.1038/298578a0
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发表时间：
1982-01-01
期刊：
影响因子：
64.8
通讯作者：
WOODLAND, HR
中科院分区：
文献类型：
--
作者：
COVENEY, J;WOODLAND, HR
自从最初发现不同细胞类型中珠蛋白基因的DNA酶I敏感性与珠蛋白基因表达相关1以来，这种关系已被证明适用于各种基因，包括卵清蛋白2、伴白蛋白3、鸡中α和β珠蛋白4、5、果蝇中的几种热休克蛋白6、7、四膜虫的r-染色质8和病毒性多瘤微小染色体9的基因。虽然由RNA聚合酶I和II转录的基因已被广泛研究，但由RNA聚合酶III转录的基因还没有。因此，我们研究了非洲爪蟾肝脏和卵母细胞核中转移RNA（tRNA）和卵子发生5S RNA基因的DNase I敏感性。卵子发生5S基因在任何已知的体细胞中不转录10，11，tRNA基因在肝细胞中转录，但在红细胞中无活性。我们在这里表明，虽然在这两种细胞类型的DNA酶I的敏感性和基因转录之间的对应关系持有良好的珠蛋白和核糖体基因，tRNA和卵细胞5S基因是DNA酶I敏感的肝细胞和红细胞核。因此，对于由聚合酶III转录的基因，敏感性和表达的对应关系被打破。
Since the initial discovery that the DNase I sensitivity of the globin genes in different cell types correlates with globin gene expression1, this relationship has been shown to hold true for a variety of genes, including the genes for ovalbumin2, conalbumin3,α- andβ-globin in chicken4,5, several heat-shock proteins inDrosophila6,7, the r-chromatin ofTetrahymena8and the viral polyoma minichromosome9. Although genes transcribed by RNA polymerases I and II have been studied extensively, the genes transcribed by RNA polymerase III have not. We have therefore investigated the DNase I sensitivity of transfer RNA (tRNA) and oogenetic 5S RNA genes in the liver and erythocyte nuclei ofXenopus laevis. The oogenetic 5S genes are not transcribed in any known somatic cell10,11, and tRNA genes are transcribed in the hepatocyte but are inactive in the erythrocyte. We show here that, although in these two cell types the correspondence between DNase I sensitivity and gene transcription holds good for globin and the ribosomal genes, the tRNA and oogenetic 5S genes are DNase I sensitive in both liver and erythrocyte nuclei. Thus for the genes transcribed by polymerase III the correspondence of sensitivity and expression breaks down.