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In this work, we study numerically the influence of the DNA torque on the movement of transcription bubbles in the potential field formed by the sequence of plasmid PTTQ18. To imitate the movement, we apply a modified sine-Gordon equation with the two additional terms that describe the effects of dissipation and the action of the DNA torsion torque, and with the coefficients that depend on the sequence of bases. We obtain the trajectories of the transcription bubbles and investigate the dependence of the trajectories on the initial bubble velocity and the DNA torsion torque. It is shown that not the initial bubble velocity but the DNA torsion torque governs the trajectories of the transcription bubbles.
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http://dx.doi.org/10.1016/j.jtbi.2018.04.036 | DOI Listing |
Soc Sci Med
August 2025
University of Bristol, Palliative and End of Life Care Research Group, Population Health Sciences, Bristol Medical School, Canynge Hall, 39 Whatley Road, Bristol, BS8 2PS, UK. Electronic address:
People bereaved during the Covid-19 pandemic experienced profoundly altered death, mourning and grieving practices. Worsened grief outcomes have been widely reported but less is known about how people coped during these unprecedented times. Using reflexive thematic analysis critically informed by theories of biographical disruption and meaning-making, we analysed 39 interview transcripts from 24 people bereaved during the pandemic in the UK.
View Article and Find Full Text PDFNat Commun
August 2025
Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, USA.
Bacterial σ factors bind RNA polymerase (E) to form holoenzyme (Eσ), conferring promoter specificity to E and playing a key role in transcription bubble formation. σ is unique among σ factors in its structure and functional mechanism, requiring activation by specialized AAA+ ATPases. Eσ forms an inactive promoter complex where the N-terminal σ region I (σ-RI) threads through a small DNA bubble.
View Article and Find Full Text PDFMol Cell
August 2025
Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ 08854, USA. Electronic address:
Transcription of the human mitochondrial DNA is initiated by POLRMT and initiation factors mitochondrial transcription factor A (TFAM) and mitochondrial transcription factor B2 (TFB2M). We present cryo-electron microscopy (cryo-EM) structures of three transcription initiation intermediates (pre-catalytic IC3 [pre-IC3], slipped-IC3, and slipped pre-IC4) catalyzing RNA synthesis by normal and slippage pathways with fully resolved transcription bubbles and RNA transcripts starting from the +1 or -1 position. The structural and biochemical studies reveal mechanisms of promoter melting, start site selection, and slippage synthesis.
View Article and Find Full Text PDFMicrosyst Nanoeng
July 2025
Department of Biophysics, Institute of Quantum Biology, Sungkyunkwan University, Suwon, 16419, South Korea.
Photothermal conversion-based quantitative polymerase chain reaction (qPCR) is a fast, sensitive, and accurate method to diagnose infectious diseases. However, they have bottlenecks in test throughput scalability, cumbersome oil cover, and a lack of multi-target capability. Here, the authors present an infectious disease diagnostic device with rapid photothermal conversion-based efficient reverse transcription (RT)-qPCR assays on a multi-target chip (idream-qPCR).
View Article and Find Full Text PDFInt J Dev Biol
June 2025
Graduate School of East-West Medical Science, Kyung Hee University, Republic of Korea.
The enhancer threshold is defined as the minimum concentration of transcription factors (TFs) required to elicit an enhancer response in a given time and space. Here, evidence is presented that the enhancer threshold is relative to promoter strength in the early embryo. The apparently inactive () minimal stripe element (MSE), in which a single Hunchback (Hb)-binding site is deleted, is functionally complemented by the promoter in transgenic embryos.
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