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The torpedo model of transcription termination asserts that the exonuclease Xrn2 attacks the 5'PO4-end exposed by nascent RNA cleavage and chases down the RNA polymerase. We tested this mechanism using a dominant-negative human Xrn2 mutant and found that it delayed termination genome-wide. Xrn2 nuclease inactivation caused strong termination defects downstream of most poly(A) sites and modest delays at some histone and U snRNA genes, suggesting that the torpedo mechanism is not limited to poly(A) site-dependent termination. A central untested feature of the torpedo model is that there is kinetic competition between the exonuclease and the pol II elongation complex. Using pol II rate mutants, we found that slow transcription robustly shifts termination upstream, and fast elongation extends the zone of termination further downstream. These results suggest that kinetic competition between elongating pol II and the Xrn2 exonuclease is integral to termination of transcription on most human genes.
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http://dx.doi.org/10.1016/j.molcel.2015.09.026 | DOI Listing |
Sci Total Environ
September 2025
Laboratoire Physico-Chimie des Matériaux, Substances Naturelles et Environnement, Faculty of Sciences and Techniques, Abdelmalek Essaâdi University, Tangier, Morocco.
Escalating concentrations of norfloxacin (NFX) in surface and wastewaters demand sustainable remediation strategies. In this study, dual-functional hydrochars were synthesized from argan nut shells (ArNS) via hydrothermal carbonization (HTC), with process conditions optimized by varying temperature (150-200 °C) and residence time (2-6 h). Among the materials, H1:5@150-4-prepared at 150 °C for 4 h with a biomass-to-water ratio of 1:5-exhibited the best performance, achieving a monolayer NFX adsorption capacity of 27.
View Article and Find Full Text PDFInorg Chem
September 2025
School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, PR China.
Confronting the dual challenges of carbon neutrality and sustainable energy, photocatalytic CO reduction requires precise control over product selectivity. This study demonstrates that surface hydroxyl (-OH) density serves as a molecular switch for reaction pathways in graphene oxide/cobalt tetraphenylporphyrin (GO/CoTPP) hybrids. By tuning the reduction degree of GO supports via gradient hydrazine hydrate treatment (0-85%), we constructed catalysts with controlled -OH concentrations.
View Article and Find Full Text PDFChem Biol Interact
September 2025
Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China. Electronic address:
Prolyl endopeptidase (PREP) drives neurodegenerative diseases through dual mechanisms involving enzymatic activity and protein-protein interactions (PPIs), yet current inhibitors predominantly target single pathways. Prolyl endopeptidase (PREP) fuels neurodegeneration via enzymatic cleavage and pathological PPIs, yet current inhibitors usually target only one facet. In this study, leveraging our developed high-sensitivity and high-specificity near-infrared fluorescent probe Z-GP-ACM, we established and validated a screening platform for PREP inhibitors with mouse brain S9 instead of the human recombinant PREP.
View Article and Find Full Text PDFInt J Biol Macromol
September 2025
Department of Biology Education, Teachers College, Kyungpook National University, Daegu, 41566, Republic of Korea; Department of Advanced Bioconvergence, BK21 FOUR KNU Center for Innovative One-Health Leaders, Kyungpook National University, Daegu, 41566, Republic of Korea. Electronic address: syy@kn
The chemical profile of brown algae Ecklonia cava was comprehensively analyzed using ultra-high-performance liquid chromatography coupled with a Q-Exactive Orbitrap mass spectrometer and GNPS molecular networking, identifying 33 components, including 27 oligomeric phloroglucinols. Among these, 10 compounds with analogous structural segments were evaluated for β-glucuronidase inhibitory activity, revealing potent inhibition by eckol, phlorofucofuroeckol A (PFF-A), dieckol, 2-phloroeckol, dioxinodehydroeckol (DHE), 8,8'-bieckol, and 6,8'-bieckol, with IC values ranging from 0.3 to 30.
View Article and Find Full Text PDFJ Colloid Interface Sci
September 2025
School of Material Electronics and Energy Storage, Zhongyuan University of Technology, Zhengzhou 450007, China. Electronic address:
Developing single-atom catalysts (SACs) with dense active sites and universal synthesis strategies remains a critical challenge. Herein, we present a scalable and universal strategy to synthesize high-density transition metal single-atom sites, anchored in nitrogen-doped porous carbon (M-SA@NC, M = Fe, Co, Ni) and investigate their oxygen reduction reaction (ORR) catalytic activity for flexible Zn-air batteries (ZABs). Using a facile coordination-pyrolysis strategy, atomically dispersed M-N sites with high metal loading are achieved.
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