Irina Artsimovitch

Jan 8, 2025 | nature.com | Daniela Gjorgjevikj |Naveen Kumar |Bing H. Wang |Tarek Hilal |Bernhard Loll |Irina Artsimovitch

AbstractMany bacteriophages modulate host transcription to favor expression of their own genomes. Phage satellite P4 polarity suppression protein, Psu, a building block of the viral capsid, inhibits hexameric transcription termination factor, ρ, by presently unknown mechanisms. Our cryogenic electron microscopy structures of ρ-Psu complexes show that Psu dimers clamp two inactive, open ρ rings and promote their expansion to higher-oligomeric states.

Aug 30, 2024 | nature.com | Bing H. Wang |Irina Artsimovitch

AbstractAfter an RNA polymerase reaches a terminator, instead of dissociating from the template, it may diffuse along the DNA and recommence RNA synthesis from the previous or a different promoter. Magnetic tweezers were used to monitor such secondary transcription and determine the effects of low forces assisting or opposing translocation, protein roadblocks, and transcription factors. Remarkably, up to 50% of Escherichia coli (E. coli) RNA polymerases diffused along the DNA after termination.