The Composition of the Arabidopsis RNA Polymerase II Transcript Elongation Complex Reveals the Interplay between Elongation and mRNA Processing Factors
The Composition of the Arabidopsis RNA Polymerase II Transcript Elongation Complex Reveals the Interplay between Elongation and mRNA Processing Factors
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DOI：
10.1105/tpc.16.00735
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发表时间：
2017-04-01
期刊：
影响因子：
11.6
通讯作者：
Grasser, Klaus D.
中科院分区：
文献类型：
--
作者：
Antosz, Wojciech;Pfab, Alexander;Grasser, Klaus D.
转录延伸因子（tef）是一组异质蛋白，在染色质环境下通过RNA聚合酶II （RNAPII）控制基因亚群转录延伸的效率。通过相互标记结合亲和纯化和质谱分析，我们发现在拟南芥中，TEFs SPT4/SPT5、SPT6、FACT、PAF1-C和TFIIS相互作用并与拉长的RNAPII相互作用，而P-TEFb不在相互作用物之列。此外，反复发现NAP1组蛋白伴侣、atp依赖性染色质重塑因子和一些组蛋白修饰酶（包括拉长酶）与tef有关。对不同TEFs组合双突变体缺陷植株的分析揭示了编码PAF1-C、FACT和TFIIS亚基的基因之间的遗传相互作用，对植物的生长发育产生协同/上位性效应。亚核定位、基因表达和染色质关联分析没有提供tef参与RNAPI（或RNAPIII）转录的证据。蛋白质组学分析还揭示了转录延伸复合体与mRNA剪接和聚腺苷化相关因子之间的多种相互作用，包括PAF1-C与聚腺苷化因子CstF的关联。因此，RNAPII转录延伸复合体代表了不同tef之间相互作用的平台，以及协调正在进行的转录与mRNA加工的平台。
Transcript elongation factors (TEFs) are a heterogeneous group of proteins that control the efficiency of transcript elongation of subsets of genes by RNA polymerase II (RNAPII) in the chromatin context. Using reciprocal tagging in combination with affinity purification and mass spectrometry, we demonstrate that in Arabidopsis thaliana, the TEFs SPT4/SPT5, SPT6, FACT, PAF1-C, and TFIIS copurified with each other and with elongating RNAPII, while P-TEFb was not among the interactors. Additionally, NAP1 histone chaperones, ATP-dependent chromatin remodeling factors, and some histone-modifying enzymes including Elongator were repeatedly found associated with TEFs. Analysis of double mutant plants defective in different combinations of TEFs revealed genetic interactions between genes encoding subunits of PAF1-C, FACT, and TFIIS, resulting in synergistic/epistatic effects on plant growth/development. Analysis of subnuclear localization, gene expression, and chromatin association did not provide evidence for an involvement of the TEFs in transcription by RNAPI (or RNAPIII). Proteomics analyses also revealed multiple interactions between the transcript elongation complex and factors involved in mRNA splicing and polyadenylation, including an association of PAF1-C with the polyadenylation factor CstF. Therefore, the RNAPII transcript elongation complex represents a platform for interactions among different TEFs, as well as for coordinating ongoing transcription with mRNA processing.