RNA functions at the initiation step of mammalian chromosomal DNA replication
RNA functions at the initiation step of mammalian chromosomal DNA replication
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DOI：
10.1242/jcs.047563
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发表时间：
2009-08-15
影响因子：
4
通讯作者：
Marheineke, Kathrin
中科院分区：
文献类型：
--
作者：
Krude, Torsten;Christov, Christo P.;Marheineke, Kathrin
非编码Y rna最近被确定为哺乳动物细胞核中染色体DNA复制的重要新因素，但其功能的机制细节尚未确定。在这里，我们确定了在哺乳动物无细胞系统中染色体DNA复制过程中Y RNA功能的执行点。我们通过DNA梳理和新生链分析，在单分子分辨率下确定了Y3 RNA降解对复制起始激活和叉进展率的影响。Y3 RNA的降解抑制G1期到S期和S期新的DNA复制叉的建立。这种抑制作用通过添加外源性Y1 RNA而被否定。相比之下，DNA复制叉的进展速率不受Y3 RNA降解或补充外源Y1 RNA的影响。这些数据表明，Y rna是哺乳动物细胞核中染色体DNA复制叉的建立所必需的，而不是延伸所必需的。我们得出结论，非编码Y RNA功能的执行点是染色体DNA复制起点的激活。
Non-coding Y RNAs have recently been identified as essential novel factors for chromosomal DNA replication in mammalian cell nuclei, but mechanistic details of their function have not been defined. Here, we identify the execution point for Y RNA function during chromosomal DNA replication in a mammalian cell-free system. We determined the effect of degradation of Y3 RNA on replication origin activation and on fork progression rates at single-molecule resolution by DNA combing and nascent-strand analysis. Degradation of Y3 RNA inhibits the establishment of new DNA replication forks at the G1- to S-phase transition and during S phase. This inhibition is negated by addition of exogenous Y1 RNA. By contrast, progression rates of DNA replication forks are not affected by degradation of Y3 RNA or supplementation with exogenous Y1 RNA. These data indicate that Y RNAs are required for the establishment, but not for the elongation, of chromosomal DNA replication forks in mammalian cell nuclei. We conclude that the execution point for non-coding Y RNA function is the activation of chromosomal DNA replication origins.