Joseph A Marsh, Sarah A Teichmann
Machine-learning algorithm uses structure prediction to spot disease-causing mutations.
September 22, 2023: Science
Qingsong Pan, Muxin Yang, Rui Feng, Andrew Chihpin Chuang, Ke An, Peter K Liaw, Xiaolei Wu, Nairong Tao, Lei Lu
Coarse-grained materials are widely accepted to display the highest strain hardening and the best tensile ductility. We experimentally report an attractive strain hardening rate throughout the deformation stage at 77 kelvin in a stable single-phase alloy with gradient dislocation cells, that even surpasses coarse-grained counterparts. Contrary to conventional understanding, the exceptional strain hardening arises from a distinctive dynamic structural refinement mechanism facilitated by the emission and motion of massive multi-orientational tiny stacking faults (planar defects), which are fundamentally distinct from the traditional linear dislocation mediated deformation...
September 14, 2023: Science
J B Climent, J C Guirado, M Pérez-Torres, J M Marcaide, L Peña-Moñino
Ultracool dwarfs are a category of astronomical objects including brown dwarfs and very low-mass stars. Radio observations of ultracool dwarfs have measured their brightness as a function of time (light-curves) and spectral energy distributions, providing insight into their magnetic fields. We present spatially resolved radio observations of the brown dwarf LSR J1835+3259 using very long baseline interferometry, which show extended radio emission. The detected morphology is consistent with the presence of a radiation belt...
August 24, 2023: Science
H Holden Thorp
No abstract text is available yet for this article.
August 24, 2023: Science
Yisui Xia, Remi Sonneville, Michael Jenkyn-Bedford, Liqin Ji, Constance Alabert, Ye Hong, Joseph T P Yeeles, Karim P M Labib
Assembly of the CDC45-MCM-GINS helicase is the key regulated step during eukaryotic DNA replication initiation. Until now, it was unclear whether metazoa require additional factors not present in yeast. Here, we show that Caenorhabditis elegans DNSN-1, the ortholog of human DONSON, functions during helicase assembly in a complex with MUS-101/TOPBP1. DNSN-1 is required to recruit the GINS complex to chromatin, and a cryo-electron microscopy structure indicates that DNSN-1 positions GINS on the MCM-2-7 helicase motor, by direct binding of DNSN-1 to GINS and MCM-3, using interfaces that we show are important for initiation and essential for viability...
August 17, 2023: Science
Yang Lim, Lukas Tamayo-Orrego, Ernst Schmid, Zygimante Tarnauskaite, Olga V Kochenova, Rhian Gruar, Sachiko Muramatsu, Luke Lynch, Aitana Verdu Schlie, Paula L Carroll, Gheorghe Chistol, Martin A M Reijns, Masato T Kanemaki, Andrew P Jackson, Johannes C Walter
CMG (Cdc45-MCM2-7-GINS) helicase assembly is the central event in eukaryotic replication initiation. In yeast, a multi-subunit "pre-Loading Complex" (pre-LC) accompanies GINS to chromatin-bound MCM2-7, leading to CMG formation. Here, we report that DONSON, a metazoan protein mutated in microcephalic primordial dwarfism, is required for CMG assembly in vertebrates. Using AlphaFold to screen for protein-protein interactions followed by experimental validation, we show that DONSON scaffolds a vertebrate pre-LC containing GINS, TOPBP1, and DNA pol ε...
August 17, 2023: Science
Takeshi Nishimura, Shogo Mori, Hiromasa Shikata, Moritaka Nakamura, Yasuko Hashiguchi, Yoshinori Abe, Takuma Hagihara, Hiroshi Y Yoshikawa, Masatsugu Toyota, Takumi Higaki, Miyo Terao Morita
Organisms have evolved under gravitational force and many sense the direction of gravity via statoliths in specialized cells. In flowering plants, starch-accumulating plastids, known as amyloplasts, act as statoliths to facilitate downstream gravitropism. The gravity sensing mechanism has long been considered a mechanosensing process by which amyloplasts transmit forces to intracellular structures, but the molecular mechanism underlying this has not been elucidated. We show here that LAZY1-LIKE (LZY) family proteins involved in statocyte gravity signaling associate with amyloplasts and its proximal plasma membrane...
August 10, 2023: Science
Zhe Jia, Zeyu Jin, Mathilde Marchandon, Thomas Ulrich, Alice-Agnes Gabriel, Wenyuan Fan, Peter Shearer, Xiaoyu Zou, John Rekoske, Fatih Bulut, Asli Garagon, Yuri Fialko
The destructive 2023 moment magnitude ( M w ) 7.8-7.7 earthquake doublet ruptured multiple segments of the East Anatolian Fault system in Turkey. We integrate multi-scale seismic and space-geodetic observations with multi-fault kinematic inversions and dynamic rupture modeling to unravel the events' complex rupture history and stress-mediated fault interactions. Our analysis reveals three sub-shear slip episodes during the initial M w 7.8 earthquake with delayed rupture initiation to the southwest. The M w 7...
August 3, 2023: Science
Alessandra Brambati, Olivia Sacco, Sarina Porcella, Joshua Heyza, Mike Kareh, Jens C Schmidt, Agnel Sfeir
Non-homologous end-joining (NHEJ) and homologous recombination (HR) are the primary pathways for repairing DNA double-strand breaks (DSBs) during interphase, while microhomology-mediated end-joining (MMEJ) has been regarded as a backup mechanism. Through CRISPR/Cas9-based synthetic lethal screens, we identify subunits of the 9-1-1 complex (RAD9A-HUS1-RAD1) and its interacting partner, RHINO, as crucial MMEJ factors. We uncover an unexpected function for RHINO in restricting MMEJ to mitosis. RHINO accumulates in M phase, undergoes PLK1 phosphorylation, and interacts with polymerase theta (Polθ), enabling its recruitment to DSBs for subsequent repair...
July 13, 2023: Science
Vishruth Girish, Asad A Lakhani, Sarah L Thompson, Christine M Scaduto, Leanne M Brown, Ryan A Hagenson, Erin L Sausville, Brianna E Mendelson, Pranav K Kandikuppa, Devon A Lukow, Monet Lou Yuan, Eric C Stevens, Sophia N Lee, Klaske M Schukken, Saron M Akalu, Anand Vasudevan, Charles Zou, Barbora Salovska, Wenxue Li, Joan C Smith, Alison M Taylor, Robert A Martienssen, Yansheng Liu, Ruping Sun, Jason M Sheltzer
Most cancers exhibit aneuploidy, but its functional significance in tumor development is controversial. Here, we describe ReDACT (<u>Re</u>storing <u>D</u>isomy in <u>A</u>neuploid cells using <u>C</u>RISPR <u>T</u>argeting), a set of chromosome engineering tools that allow us to eliminate specific aneuploidies from cancer genomes. Using ReDACT, we created a panel of isogenic cells that have or lack common aneuploidies, and we demonstrate that trisomy of chromosome 1q is required for malignant growth in cancers harboring this alteration...
July 6, 2023: Science
Min Zhang, Anna Jungblut, Franziska Kunert, Luis Hauptmann, Thomas Hoffmann, Olga Kolesnikova, Felix Metzner, Manuela Moldt, Felix Weis, Frank DiMaio, Karl-Peter Hopfner, Sebastian Eustermann
Loss of H2A-H2B histone dimers is a hallmark of actively transcribed genes, but how the cellular machinery functions in the context of non-canonical nucleosomal particles remains largely elusive. Here, we report the structural mechanism for ATP-dependent chromatin remodeling of hexasomes by the INO80 complex. We show how INO80 recognizes non-canonical DNA and histone features of hexasomes emerging from the loss of H2A-H2B. A large structural re-arrangement switches the catalytic core of INO80 into a distinct, spin-rotated mode of remodeling, while its nuclear actin module remains tethered to long stretches of unwrapped linker DNA...
June 29, 2023: Science
Hao Wu, Elise N Muñoz, Laura J Hsieh, Un Seng Chio, Muryam A Gourdet, Geeta J Narlikar, Yifan Cheng
Unlike other chromatin remodelers, INO80 preferentially mobilizes hexasomes, which can form during transcription. Why INO80 prefers hexasomes over nucleosomes remains unclear. Here, we report structures of S. cerevisiae INO80 bound to a hexasome or a nucleosome. INO80 binds the two substrates in substantially different orientations. On a hexasome, INO80 places its ATPase subunit, Ino80, at superhelical location (SHL)-2, across from SHL-6/-7 as previously seen on nucleosomes. Our results suggest that INO80 action on hexasomes resembles action by other remodelers on nucleosomes, such that Ino80 is maximally active near SHL-2...
June 28, 2023: Science
Jiarui Song, Anne R Gooding, Wayne O Hemphill, Brittney D Love, Anne Robertson, Liqi Yao, Leonard I Zon, Trista E North, Vignesh Kasinath, Thomas R Cech
Polycomb repressive complex 2 (PRC2) silences genes through trimethylation of histone H3K27. PRC2 associates with numerous precursor messenger RNAs (pre-mRNAs) and long noncoding RNAs (lncRNAs) with a binding preference for G-quadruplex RNA. In this work, we present a 3.3-Å-resolution cryo-electron microscopy structure of PRC2 bound to a G-quadruplex RNA. Notably, RNA mediates the dimerization of PRC2 by binding both protomers and inducing a protein interface composed of two copies of the catalytic subunit EZH2, thereby blocking nucleosome DNA interaction and histone H3 tail accessibility...
September 22, 2023: Science
Kailash Chandra Mangalhara, Siva Karthik Varanasi, Melissa A Johnson, Mannix J Burns, Gladys R Rojas, Pau B Esparza Moltó, Alva G Sainz, Nimesha Tadepalle, Keene L Abbott, Gaurav Mendiratta, Dan Chen, Yagmur Farsakoglu, Tenzin Kunchok, Filipe Araujo Hoffmann, Bianca Parisi, Mercedes Rincon, Matthew G Vander Heiden, Marcus Bosenberg, Diana C Hargreaves, Susan M Kaech, Gerald S Shadel
Although tumor growth requires the mitochondrial electron transport chain (ETC), the relative contribution of complex I (CI) and complex II (CII), the gatekeepers for initiating electron flow, remains unclear. In this work, we report that the loss of CII, but not that of CI, reduces melanoma tumor growth by increasing antigen presentation and T cell-mediated killing. This is driven by succinate-mediated transcriptional and epigenetic activation of major histocompatibility complex-antigen processing and presentation (MHC-APP) genes independent of interferon signaling...
September 22, 2023: Science
Jordan W Squair, Marco Milano, Alexandra de Coucy, Matthieu Gautier, Michael A Skinnider, Nicholas D James, Newton Cho, Anna Lasne, Claudia Kathe, Thomas H Hutson, Steven Ceto, Laetitia Baud, Katia Galan, Viviana Aureli, Achilleas Laskaratos, Quentin Barraud, Timothy J Deming, Richie E Kohman, Bernard L Schneider, Zhigang He, Jocelyne Bloch, Michael V Sofroniew, Gregoire Courtine, Mark A Anderson
Axon regeneration can be induced across anatomically complete spinal cord injury (SCI), but robust functional restoration has been elusive. Whether restoring neurological functions requires directed regeneration of axons from specific neuronal subpopulations to their natural target regions remains unclear. To address this question, we applied projection-specific and comparative single-nucleus RNA sequencing to identify neuronal subpopulations that restore walking after incomplete SCI. We show that chemoattracting and guiding the transected axons of these neurons to their natural target region led to substantial recovery of walking after complete SCI in mice, whereas regeneration of axons simply across the lesion had no effect...
September 22, 2023: Science
Terrie M Williams
From surfboard-stealing sea otters to sailboat-chomping killer whales, the summer of 2023 was a landmark year of wild animal antics. Why is wildlife suddenly interacting with humans and their toys in this way? Speculation and headlines have espoused theories about learned behaviors due to enticements with food, increased intrusion, and proximity of humans in wild habitats, as well as aberrant animal responses instigated by oceanic noise or disease-related neurological disorders. However, the most honest answer is, "We don't really know...
September 22, 2023: Science
Daniel Rubinoff, Samuel M 'Ohukani'ōhi'a Gon
No abstract text is available yet for this article.
September 22, 2023: Science
Dennis Normile
Sudden revamp would trim basic research spending while boosting biomedical innovation, space, and other fields.
September 22, 2023: Science
Longwu Liang, Mingxing Chen, Jiafan Cheng
No abstract text is available yet for this article.
September 22, 2023: Science
Sergiy Kalnaus, Nancy J Dudney, Andrew S Westover, Erik Herbert, Steve Hackney
Solid-state batteries with lithium metal anodes have the potential for higher energy density, longer lifetime, wider operating temperature, and increased safety. Although the bulk of the research has focused on improving transport kinetics and electrochemical stability of the materials and interfaces, there are also critical challenges that require investigation of the mechanics of materials. In batteries with solid-solid interfaces, mechanical contacts, and the development of stresses during operation of the solid-state batteries, become as critical as the electrochemical stability to keep steady charge transfer at these interfaces...
September 22, 2023: Science
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