Acharya Narottam, Haracska Lajos, Prakash Satya, Prakash Louise
Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, 301 University Blvd., Galveston, TX 77555-1061, USA.
Mol Cell Biol. 2007 Dec;27(23):8401-8. doi: 10.1128/MCB.01478-07. Epub 2007 Sep 17.
In Saccharomyces cerevisiae, Rev1 functions in translesion DNA synthesis (TLS) together with polymerase zeta (Pol zeta), comprised of the Rev3 catalytic and Rev7 accessory subunits. Rev1 plays an indispensable structural role in promoting Pol zeta function, and deletion of the Rev1-C terminal region that is involved in physical interactions with Rev3 inactivates Pol zeta function in TLS. In humans, however, Rev1 has been shown to physically interact with the Y-family polymerases Pol eta, Pol iota, and Pol kappa, and the Rev1 C terminus mediates these interactions. Since all the available genetic and biochemical evidence in yeast support the requirement of Rev1 as a structural element for Pol zeta and not for Pol eta, these observations have raised the possibility that in its structural role, Rev1 has diverged between yeast and humans. Here we show that although in yeast a stable Rev1-Pol eta complex can be formed, this complex formation involves the polymerase-associated domain of Rev1 and not the Rev1 C terminus as in humans. We also found that the DNA synthesis activity of Rev1 is enhanced in this complex. We discuss the implications of these and other observations for the possible divergence of Rev1's structural role between yeast and humans.
在酿酒酵母中，Rev1与由Rev3催化亚基和Rev7辅助亚基组成的聚合酶ζ（Pol ζ）一起参与跨损伤DNA合成（TLS）。Rev1在促进Pol ζ功能方面发挥着不可或缺的结构作用，缺失与Rev3发生物理相互作用的Rev1 C末端区域会使TLS中的Pol ζ功能失活。然而，在人类中，Rev1已被证明可与Y家族聚合酶Pol η、Pol ι和Pol κ发生物理相互作用，且Rev1 C末端介导了这些相互作用。由于酵母中所有现有的遗传和生化证据均支持Rev1作为Pol ζ而非Pol η的结构元件的必要性，这些观察结果引发了一种可能性，即Rev1在其结构作用方面在酵母和人类之间存在差异。在这里我们表明，尽管在酵母中可以形成稳定的Rev1-Pol η复合物，但这种复合物的形成涉及Rev1的聚合酶相关结构域，而非像在人类中那样涉及Rev1 C末端。我们还发现，在此复合物中Rev1的DNA合成活性增强。我们讨论了这些以及其他观察结果对于Rev1在酵母和人类之间结构作用可能存在差异的意义。
