Franco Alexa A, Lam Wendy M, Burgers Peter M, Kaufman Paul D
Lawrence Berkeley National Laboratory and Department of Molecular and Cell Biology, University of California, Berkeley, 94720, USA.
Genes Dev. 2005 Jun 1;19(11):1365-75. doi: 10.1101/gad.1305005. Epub 2005 May 18.
Chromatin assembly and DNA replication are temporally coupled, and DNA replication in the absence of histone synthesis causes inviability. Here we demonstrate that chromatin assembly factor Asf1 also affects DNA replication. In budding yeast cells lacking Asf1, the amounts of several DNA replication proteins, including replication factor C (RFC), proliferating cell nuclear antigen (PCNA), and DNA polymerase epsilon (Pol epsilon), are reduced at stalled replication forks. In contrast, DNA polymerase alpha (Pol alpha) accumulates to higher than normal levels at stalled forks in asf1Delta cells. Using purified, recombinant proteins, we demonstrate that RFC directly binds Asf1 and can recruit Asf1 to DNA molecules in vitro. We conclude that histone chaperone protein Asf1 maintains a subset of replication elongation factors at stalled replication forks and directly interacts with the replication machinery.
染色质组装与DNA复制在时间上是偶联的，并且在没有组蛋白合成的情况下进行DNA复制会导致细胞无法存活。在此，我们证明染色质组装因子Asf1也会影响DNA复制。在缺乏Asf1的芽殖酵母细胞中，包括复制因子C（RFC）、增殖细胞核抗原（PCNA）和DNA聚合酶ε（Pol ε）在内的几种DNA复制蛋白的量在停滞的复制叉处减少。相反，在asf1Δ细胞中，DNA聚合酶α（Pol α）在停滞的复制叉处积累至高于正常水平。使用纯化的重组蛋白，我们证明RFC直接结合Asf1并能在体外将Asf1募集到DNA分子上。我们得出结论，组蛋白伴侣蛋白Asf1在停滞的复制叉处维持一部分复制延伸因子，并直接与复制机制相互作用。
