42
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: not found
      • Article: not found

      Structure of the complete elongation complex of RNA polymerase II with basal factors

      Read this article at

      ScienceOpenPublisherPubMed
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          In the early stage of transcription, eukaryotic RNA polymerase II (Pol II) exchanges initiation factors with elongation factors to form an elongation complex (EC) for processive transcription. Here, we report the structure of the Pol II EC bound with the basal elongation factors Spt4/5, Elf1, and TFIIS. Spt4/5 (the Spt4/Spt5 complex) and Elf1 modify a wide area of the Pol II surface. Elf1 bridges the Pol II central cleft, completing the "DNA entry tunnel" for downstream DNA. Spt4 and the Spt5 NGN and KOW1 domains encircle the upstream DNA, constituting a "DNA exit tunnel". The Spt5 KOW4 and KOW5 domains augment the "RNA exit tunnel", directing the exiting nascent RNA. Thus, the EC establishes a completely different transcription/regulation platform from that of the initiation complexes.

          Related collections

          Most cited references28

          • Record: found
          • Abstract: found
          • Article: not found

          Structural basis of transcription: RNA polymerase II at 2.8 angstrom resolution.

          Structures of a 10-subunit yeast RNA polymerase II have been derived from two crystal forms at 2.8 and 3.1 angstrom resolution. Comparison of the structures reveals a division of the polymerase into four mobile modules, including a clamp, shown previously to swing over the active center. In the 2.8 angstrom structure, the clamp is in an open state, allowing entry of straight promoter DNA for the initiation of transcription. Three loops extending from the clamp may play roles in RNA unwinding and DNA rewinding during transcription. A 2.8 angstrom difference Fourier map reveals two metal ions at the active site, one persistently bound and the other possibly exchangeable during RNA synthesis. The results also provide evidence for RNA exit in the vicinity of the carboxyl-terminal repeat domain, coupling synthesis to RNA processing by enzymes bound to this domain.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            P-TEFb-mediated phosphorylation of hSpt5 C-terminal repeats is critical for processive transcription elongation.

            Human DSIF, a heterodimer composed of hSpt4 and hSpt5, plays opposing roles in transcription elongation by RNA polymerase II (RNA Pol II). Here, we describe an evolutionarily conserved repetitive heptapeptide motif (consensus = G-S-R/Q-T-P) in the C-terminal region (CTR) of hSpt5, which, like the C-terminal domain (CTD) of RNA Pol II, is highly phosphorylated by P-TEFb. Thr-4 residues of the CTR repeats are functionally important phosphorylation sites. In vitro, Thr-4 phosphorylation is critical for the elongation activation activity of DSIF, but not to its elongation repression activity. In vivo, Thr-4 phosphorylation is critical for epidermal growth factor (EGF)-inducible transcription of c-fos and for efficient progression of RNA Pol II along the gene. We consider this phosphorylation to be a switch that converts DSIF from a repressor to an activator. We propose the "mini-CTD" hypothesis, in which phosphorylated CTR is thought to function in a manner analogous to phosphorylated CTD, serving as an additional code for active elongation complexes.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Architecture of the RNA polymerase II-Mediator core initiation complex.

              The conserved co-activator complex Mediator enables regulated transcription initiation by RNA polymerase (Pol) II. Here we reconstitute an active 15-subunit core Mediator (cMed) comprising all essential Mediator subunits from Saccharomyces cerevisiae. The cryo-electron microscopic structure of cMed bound to a core initiation complex was determined at 9.7 Å resolution. cMed binds Pol II around the Rpb4-Rpb7 stalk near the carboxy-terminal domain (CTD). The Mediator head module binds the Pol II dock and the TFIIB ribbon and stabilizes the initiation complex. The Mediator middle module extends to the Pol II foot with a 'plank' that may influence polymerase conformation. The Mediator subunit Med14 forms a 'beam' between the head and middle modules and connects to the tail module that is predicted to bind transcription activators located on upstream DNA. The Mediator 'arm' and 'hook' domains contribute to a 'cradle' that may position the CTD and TFIIH kinase to stimulate Pol II phosphorylation.
                Bookmark

                Author and article information

                Journal
                Science
                Science
                American Association for the Advancement of Science (AAAS)
                0036-8075
                1095-9203
                August 31 2017
                September 01 2017
                September 01 2017
                August 03 2017
                : 357
                : 6354
                : 921-924
                Article
                10.1126/science.aan8552
                28775211
                3841baa9-4174-42cc-8ec5-47165e11d74c
                © 2017

                http://www.sciencemag.org/about/science-licenses-journal-article-reuse

                History

                Comments

                Comment on this article