Characterization of the interactions of mammalian RNA polymerase I associated proteins PAF53 and PAF49.
Characterization of the interactions of mammalian RNA polymerase I associated proteins PAF53 and PAF49.
复制标题
哺乳动物 RNA 聚合酶 I 相关蛋白 PAF53 和 PAF49 相互作用的表征。
DOI：
10.1021/bi300408q
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发表时间：
2012
期刊：
影响因子：
2.9
通讯作者：
Rothblum,LawrenceI
中科院分区：
文献类型：
--
作者：
Penrod,Yvonne;Rothblum,Katrina;Rothblum,LawrenceI
村松正美的实验室证明了RNA聚合酶I(POL I)相关因子PAF53在哺乳动物rRNA转录中的关键作用。他们还确定了第二种聚合酶相关因子PAF49。PAF49和PAF53都与RNA聚合酶I分子的那部分在体外转录启动中起作用。PAF49和PAF53是酵母RNA聚合酶I的两个亚单位A34.5和A49在哺乳动物中的同源物，这两个亚单位在酵母RNA聚合酶I中形成了一个与TFIIF相关的亚复合体。将我们的结果与酵母A34.5和A49的结构研究相比较，表明酵母和哺乳动物的蛋白质实际上可能具有结构相似之处。事实上，缺失突变数据证实和扩展了结构研究。例如，PAF49的41-86位氨基酸足以为异源二聚提供基础，在电子结构分析中预测，该区域可能具有与酵母A34.5的同源区相似的结构。这些相似性本身并不足以让蛋白质形成种间异二聚体。然而，将酵母A34.5的52-98位氨基酸替换为哺乳动物PAF49的41-86位氨基酸，得到了一种可以与小鼠PAF53异源二聚体的蛋白质。
Masami Muramatsu’s laboratory demonstrated the critical role of RNA polymerase I (Pol I)-associated factor PAF53 in mammalian rRNA transcription. They have also identified a second polymerase associated factor, PAF49. Both PAF49 and PAF53 copurify with that fraction of the RNA polymerase I molecules that can function in transcription initiationin vitro. PAF49 and PAF53 are the mammalian homologues of two subunits of yeast RNA polymerase I, A34.5 and A49, that form a TFIIF-related subcomplex in yeast RNA polymerase I. In light of those publications, we investigated the interactions between various deletion and substitution mutants of mammalian PAF49 and PAF53 with the purpose of identifying those domains of the mammalian proteins that interact. Comparison of our results with structural studies on yeast A34.5 and A49 demonstrates that the yeast and mammalian proteins may in fact share structural similarities. In fact, the deletion mutagenesis data confirmed and extended the structural studies. For example, amino acids 41–86 of PAF49 were sufficient to provide the basis for heterodimerization.In silicostructural analysis predicted that this region could assume a structure similar to the homologous region of yeast A34.5. Those similarities are insufficient, by themselves, for the proteins to form interspecific heterodimers. However, substitution of amino acids 52–98 of yeast A34.5 with amino acids 41–86 of mammalian PAF49 resulted in a protein that could heterodimerize with mouse PAF53.