共查询到20条相似文献，搜索用时 578 毫秒
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Egloff S O'Reilly D Chapman RD Taylor A Tanzhaus K Pitts L Eick D Murphy S 《Science (New York, N.Y.)》2007,318(5857):1777-1779
RNA polymerase II (Pol II) transcribes genes that encode proteins and noncoding small nuclear RNAs (snRNAs). The carboxyl-terminal repeat domain (CTD) of the largest subunit of mammalian RNA Pol II, comprising tandem repeats of the heptapeptide consensus Tyr1-Ser2-Pro3-Thr4-Ser5-Pro6-Ser7, is required for expression of both gene types. We show that mutation of serine-7 to alanine causes a specific defect in snRNA gene expression. We also present evidence that phosphorylation of serine-7 facilitates interaction with the snRNA gene-specific Integrator complex. These findings assign a biological function to this amino acid and highlight a gene type-specific requirement for a residue within the CTD heptapeptide, supporting the existence of a CTD code. 相似文献
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Reciprocal binding of PARP-1 and histone H1 at promoters specifies transcriptional outcomes 总被引：1，自引：0，他引：1
Krishnakumar R Gamble MJ Frizzell KM Berrocal JG Kininis M Kraus WL 《Science (New York, N.Y.)》2008,319(5864):819-821
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Ferrari R Pellegrini M Horwitz GA Xie W Berk AJ Kurdistani SK 《Science (New York, N.Y.)》2008,321(5892):1086-1088
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Lee MG Villa R Trojer P Norman J Yan KP Reinberg D Di Croce L Shiekhattar R 《Science (New York, N.Y.)》2007,318(5849):447-450
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Groth A Corpet A Cook AJ Roche D Bartek J Lukas J Almouzni G 《Science (New York, N.Y.)》2007,318(5858):1928-1931
DNA replication in eukaryotes requires nucleosome disruption ahead of the replication fork and reassembly behind. An unresolved issue concerns how histone dynamics are coordinated with fork progression to maintain chromosomal stability. Here, we characterize a complex in which the human histone chaperone Asf1 and MCM2-7, the putative replicative helicase, are connected through a histone H3-H4 bridge. Depletion of Asf1 by RNA interference impedes DNA unwinding at replication sites, and similar defects arise from overproduction of new histone H3-H4 that compromises Asf1 function. These data link Asf1 chaperone function, histone supply, and replicative unwinding of DNA in chromatin. We propose that Asf1, as a histone acceptor and donor, handles parental and new histones at the replication fork via an Asf1-(H3-H4)-MCM2-7 intermediate and thus provides a means to fine-tune replication fork progression and histone supply and demand. 相似文献
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RNA polymerase IV directs silencing of endogenous DNA 总被引：1，自引：0，他引：1
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Shogren-Knaak M Ishii H Sun JM Pazin MJ Davie JR Peterson CL 《Science (New York, N.Y.)》2006,311(5762):844-847
Acetylation of histone H4 on lysine 16 (H4-K16Ac) is a prevalent and reversible posttranslational chromatin modification in eukaryotes. To characterize the structural and functional role of this mark, we used a native chemical ligation strategy to generate histone H4 that was homogeneously acetylated at K16. The incorporation of this modified histone into nucleosomal arrays inhibits the formation of compact 30-nanometer-like fibers and impedes the ability of chromatin to form cross-fiber interactions. H4-K16Ac also inhibits the ability of the adenosine triphosphate-utilizing chromatin assembly and remodeling enzyme ACF to mobilize a mononucleosome, indicating that this single histone modification modulates both higher order chromatin structure and functional interactions between a nonhistone protein and the chromatin fiber. 相似文献
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Ogawa H Ishiguro K Gaubatz S Livingston DM Nakatani Y 《Science (New York, N.Y.)》2002,296(5570):1132-1136
E2F-6 contributes to gene silencing in a manner independent of retinoblastoma protein family members. To better elucidate the molecular mechanism of repression by E2F-6, we have purified the factor from cultured cells. E2F-6 is found in a multimeric protein complex that contains Mga and Max, and thus the complex can bind not only to the E2F-binding site but also to Myc- and Brachyury-binding sites. Moreover, the complex contains chromatin modifiers such as a novel histone methyltransferase that modifies lysine 9 of histone H3, HP1gamma, and Polycomb group (PcG) proteins. The E2F-6 complex preferentially occupies target promoters in G0 cells rather than in G1 cells. These data suggest that these chromatin modifiers contribute to silencing of E2F- and Myc-responsive genes in quiescent cells. 相似文献