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RNA病毒RNA依赖的RNA聚合酶的结构与功能
RNA病毒一般传播迅速,给人类和自然造成巨大危害和威胁.许多RNA病毒的结构蛋白在基础研究和应用方面已日趋完善.相比之下,就非结构蛋白(NS)所做的研究较少,存在许多未知问题.在这些非结构蛋白中,病毒自身编码的RNA依赖的RNA聚合酶(RNA-dependent RNA polymerase,RdRP)对病毒的复制起关键作用.对RdRP的研究不仅使对病毒RNA复制的机制更精细明了,且有可能提供新的抗病毒靶标和诊断试剂.本文对RdRP特别是动物RNA病毒RdRP的结果与功能作一综述.
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Polycomb repression complex 2 ( PRC2 ) component EZH2 tri-methylates H3 K27 and exerts ep-igenetic repression on target gene expression. EZH2-mediated epigenetic control of RNA polymerase II(Pol II) transcribed coding gene transcription has been well established. However, little is known about EZH2-mediated epigenetic regulation of RNA polymerase III( Pol III) transcription. Here we present a paradigm that EZH2 is in-volved in the repression of Pol III transcription via interaction with transcriptional factor complex IIIC ( TFIIIC ) . EZH2 and H3K27 me3 cooccupy the promoter of tRNATyr, 5S rRNA and 7SL RNA genes. Depletion of EZH2 or inhibition of EZH2 methyl transferase activity led to upregulation of Pol III target gene transcription. EZH2-media-ted repression of Pol III transcribed gene expression requires presence of SUZ12 . SUZ12 was able to interact with TFIIIC complex and knockdown of SUZ12 decreased occupancy of EZH2 and H3 K27 me3 at the promoter of Pol III target genes. Our findings pointed out a previously unidentified role of PRC2 complex in suppressing transcription of Pol III transcribed non-translated RNA genes, putting Pol III on a new layer of epigenetic regulation.
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流感病毒RNA聚合酶的结构和功能研究进展
流行性感冒病毒(influenza virus), 简称流感病毒,是引起流行性感冒(简称流感)的病原体.在20世纪人类遭受了4次流感大流行,致使数千万人失去了生命[1].近几年来禽流感等跨越种属障碍给人类健康和安全带来了更大的威胁,使人们清楚地认识到加强和完善对流感这类经呼吸道传播并有可能来源于动物的传染性疾病的预防、控制和治疗具有重大科学意义和实际应用价值[2].
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关键词： RNA polymerase
