The 19S regulatory particle of the proteasome is required for efficient transcription elongation by RNA polymerase II
The 19S regulatory particle of the proteasome is required for efficient transcription elongation by RNA polymerase II
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DOI：
10.1016/s1097-2765(01)00250-7
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发表时间：
2001-05-01
期刊：
影响因子：
16
通讯作者：
Johnston, SA
中科院分区：
文献类型：
--
作者：
Ferdous, A;Gonzalez, F;Johnston, SA
一般认为，26 S蛋白酶体的19 S调节颗粒的主要或甚至唯一活性是促进20 S-核心亚基降解聚泛素化蛋白。然而，我们目前的证据表明，19 S复合物是所需的RNA聚合酶II（RNAP II）在体外和体内的有效延长。首先，携带编码19 S组分的SUG 1和SUG 2的等位基因的酵母菌株表现出指示伸长缺陷的表型。第二，在体外转录被抑制的抗体对Sug 1，或通过热灭活温度敏感的Sug 1突变体与恢复延长添加免疫纯化的19 S复合物。最后，Cdc 68，一种已知的延伸因子，与19 S复合物共免疫沉淀，表明物理相互作用。蛋白酶体的20 S蛋白水解核心的抑制对延伸没有影响。这项工作定义了RNAP II转录中19 S复合物的非蛋白水解作用。
It is generally thought that the primary or even sole activity of the 19S regulatory particle of the 26S proteasome is to facilitate the degradation of polyubiquitinated proteins by the 20S-core subunit. However, we present evidence that the 19S complex is required for efficient elongation of RNA polymerase II (RNAP II) in vitro and in vivo. First, yeast strains carrying alleles of SUGI and SUG2, encoding 19S components, exhibit phenotypes indicative of elongation defects. Second, in vitro transcription is inhibited by antibodies raised against Sug1, or by heat-inactivating temperature-sensitive Sug1 mutants with restoration of elongation by addition of immunopurified 19S complex. Finally, Cdc68, a known elongation factor, coimmunoprecipitates with the 19S complex, indicating a physical interaction. Inhibition of the 20S proteolytic core of the proteasome has no effect on elongation. This work defines a nonproteolytic role for the 19S complex in RNAP II transcription.