TAILIEUCHUNG - Báo cáo khoa học: Molecular bioimaging of gene transcription

In the first half of the talk, the current state of our ongoing structure-function analysis of the mRNA transcription cycle will be dis-cussed. The crystallographic structures of the complete 12-subunit RNA polymerase II in free form and with bound DNA and RNA have been determined as atomic models. The structure of the complete Pol II elongation complex bound by the transcript cleavage factor TFIIS explained how Pol II uses a single tunable active site for both RNA synthesis and RNA cleavage. | Tuesday Symposia Lectures Tuesday July 10 2007 A3-L1 To be announced. A3-L2 A. Fisher Imperial College London UK No abstract available. 31 Symposia Lectures Tuesday A3-L3 DNA damage checkpoints dynamics in live cells and relevance to cancer J. Bartek Institute of Cancer Biology Copenhagen DENMARK No abstract available. A3-L4 Opening PANdora s box insights into nuclear RNA decay in mammalian cells J. Steitz1 N. Conrad2 S. Mili3 K. Uyhazi2 M. Shu4 E. Marshall5 and J. Pawlicki2 1Yale HHMI New Haven CT USA 2Yale New Haven CT USA 3University of VA Charlottesville VA USA 4Yale University New Haven CT USA Stanford Stanford CA USA Kaposi s sarcoma-associated herpesvirus KSHV PAN polyadenylated nuclear RNA a 1 kb RNA polymerase II transcript accumulates to very high levels in the nucleus of lytically infected cells. We identified a 79-nt element the ENE which acts post-transcriptionally to achieve these high levels and also significantly increases nuclear RNA expression from an intronless beta-globin construct. PAN RNA exhibits two-component exponential decay kinetics with some transcripts undergoing rapid t1 2 15 min and others slow t1 2 --3 h decay. The ENE renders an RNA less likely to be in the pool of rapidly degraded transcripts. ENE activity is dependent on the presence of a polyA tail both in vitro and in vivo. The ENE leads to increased in vivo accumulation of beta-globin pre-mRNA transcripts with mutant but not wildtype splice sites. These data suggest that the ENE counteracts a novel rapid decay pathway that is part of a surveillance system for polyadenylated RNA transcripts in mammalian cell nuclei. Recent mutational studies indicate that the ENE forms a specific snoRNA-like secondary structure that acts to stabilize polyadenylated transcripts by sequestering the polyA tail from the action of deadenylases thereby preventing the first step in decay. The surprising effect of the ENE on primary microRNA pri-miRNA transcripts and on the regulation of nuclear steps .

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• cell structure
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• analysis of cytoplasmic
• oxidation
• Crystal structure
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• breast cancer
• chemical reaction
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