Genome-wide hierarchy of replication origin usage in Saccharomyces cerevisiae.
Genome-wide hierarchy of replication origin usage in Saccharomyces cerevisiae.
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DOI：
10.1371/journal.pgen.0020141
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发表时间：
2006-09-08
期刊：
影响因子：
4.5
通讯作者：
Tye BK
中科院分区：
文献类型：
--
作者：
Donato JJ;Chung SC;Tye BK
基因组中的复制起始点在其碱基序列以及对DNA复制的时间和细胞周期调节信号的响应方面存在固有的不同。为了研究影响全基因组DNA复制启动效率的染色体决定因素，我们利用了最初用于在酿酒酵母中分离复制起始突变体的反向策略。在酵母中，从染色体分离的复制起点支持质粒的自主复制。这些复制起始点，无论是在染色体还是在质粒的背景下，都将在野生型细胞中有效地启动，但在复制启动的早期步骤中存在缺陷的突变体中显示出截然不同的激活效率。在这样的突变体中，自主复制序列(ARS)的基因组文库的连续传代使我们能够选择具有结构性活性的ARS。我们发现了与局部转录模式相关的ARS优先启动的层次结构。这种优先使用在复制前复合体(Pre-RC)的组装缺陷的突变体中得到增强，但在Pre-RC的激活中缺陷的突变体中不增强。我们的发现与局部转录对大多数复制起始处前RC组装的干扰是一致的。在后生动物的发育过程中，受DNA合成速率调控的S相的长度变化很大。这一调控的关键是不同发育阶段利用的复制起始点的数量。一个基本的问题是，在不同的条件下，复制起点的使用是否存在层次结构，如果是，优先使用的决定因素是什么。在酿酒酵母中，分离于DNA片段中的复制起点被称为自主复制序列(ARSS)。为了深入了解调控复制起始点使用的决定因素，确定了在不利的复制起始条件下优先使用的基因组ARS。其中一个决定因素似乎是局部转录模式。针对ARS的转录活性与该ARS的复制起始效率降低相关。这种转录干扰似乎是针对复制前复合体的组装。这些结果与在非洲爪哇早期发育的胚胎中观察到的不受调控的启动模式一致，这些胚胎没有转录。在决定复制起点使用效率方面，其他尚待确定的因素也很重要。
Replication origins in a genome are inherently different in their base sequence and in their response to temporal and cell cycle regulation signals for DNA replication. To investigate the chromosomal determinants that influence the efficiency of initiation of DNA replication genome-wide, we made use of a reverse strategy originally used for the isolation of replication initiation mutants in Saccharomyces cerevisiae. In yeast, replication origins isolated from chromosomes support the autonomous replication of plasmids. These replication origins, whether in the context of a chromosome or a plasmid, will initiate efficiently in wild-type cells but show a dramatically contrasted efficiency of activation in mutants defective in the early steps of replication initiation. Serial passages of a genomic library of autonomously replicating sequences (ARSs) in such a mutant allowed us to select for constitutively active ARSs. We found a hierarchy of preferential initiation of ARSs that correlates with local transcription patterns. This preferential usage is enhanced in mutants defective in the assembly of the prereplication complex (pre-RC) but not in mutants defective in the activation of the pre-RC. Our findings are consistent with an interference of local transcription with the assembly of the pre-RC at a majority of replication origins. The length of S phase regulated by the rate of DNA synthesis varies dramatically during the development of metazoans. Key to this regulation is the number of replication origins utilized in different developmental stages. A fundamental question is whether there is a hierarchy in the usage of replication origins under different conditions and if so, what are the determinants for preferential usage. In Saccharomyces cerevisiae, replication origins isolated in DNA fragments are known as autonomously replicating sequences (ARSs). To gain insight into the determinants that regulate replication origin usage, genomic ARSs that are preferentially used under adverse conditions for replication initiation were identified. One of the determinants appears to be the local transcription pattern. Transcriptional activity directed towards an ARS correlates with reduced efficiency of replication initiation of that ARS. This transcriptional interference appears to be targeted at the assembly of the prereplication complex. These results are consistent with the deregulated initiation patterns observed in early developing Xenopus embryos that are devoid of transcription. Other yet-to-be-identified factors are also important in determining the efficiency of replication origin usage.
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影响因子：
4.8
作者：
Fitch, MJ;Donato, JJ;Tye, BK
通讯作者：
Tye, BK
影响因子：
5.3
作者：
HEINZEL, SS;KRYSAN, PJ;CALOS, MP
通讯作者：
CALOS, MP
影响因子：
56.9
作者：
MARAHRENS, Y;STILLMAN, B
通讯作者：
STILLMAN, B
影响因子：
4.8
作者：
Chang, VK;Fitch, MJ;Tye, BK
通讯作者：
Tye, BK
影响因子：
4.3
作者：
Bielinsky, Anja-Katrin
通讯作者：
Bielinsky, Anja-Katrin