253 results match your criteria: "Gene Center and Department of Biochemistry[Affiliation]"

RNA-sensing TLRs are strategically positioned in the endolysosome to detect incoming nonself RNA. RNase T2 plays a critical role in processing long, structured RNA into short oligoribonucleotides that engage TLR7 or TLR8. In addition to its positive regulatory role, RNase T2 also restricts RNA recognition through unknown mechanisms, as patients deficient in RNase T2 suffer from neuroinflammation.

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Inter-chromosomal transcription hubs shape the 3D genome architecture of African trypanosomes.

Nat Commun

December 2024

Division of Experimental Parasitology, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, 82152, Planegg-Martinsried, Germany.

The eukaryotic nucleus exhibits a highly organized 3D genome architecture, with RNA transcription and processing confined to specific nuclear structures. While intra-chromosomal interactions, such as promoter-enhancer dynamics, are well-studied, the role of inter-chromosomal interactions remains poorly understood. Investigating these interactions in mammalian cells is challenging due to large genome sizes and the need for deep sequencing.

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Phosphorylation-mediated conformational change regulates human SLFN11.

Nat Commun

December 2024

Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen Straße 25, 81377, Munich, Germany.

Human Schlafen 11 (SLFN11) is sensitizing cells to DNA damaging agents by irreversibly blocking stalled replication forks, making it a potential predictive biomarker in chemotherapy. Furthermore, SLFN11 acts as a pattern recognition receptor for single-stranded DNA (ssDNA) and functions as an antiviral restriction factor, targeting translation in a codon-usage-dependent manner through its endoribonuclease activity. However, the regulation of the various SLFN11 functions and enzymatic activities remains enigmatic.

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Transcription-coupled repair of DNA-protein crosslinks.

Trends Cell Biol

November 2024

Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany. Electronic address:

Article Synopsis
  • - DNA-protein crosslinks (DPCs) are toxic DNA damage caused by various factors and can hinder essential processes like DNA replication and transcription, which are critical for cell function.
  • - Recent advancements in research have revealed a transcription-coupled DPC repair pathway triggered when RNA polymerase II (RNAPII) gets stalled, leading to the activation of specific proteins that help remove the crosslinks.
  • - Deficiencies in this repair process, specifically due to the malfunction of proteins CSB or CSA, may contribute to the complex symptoms observed in patients with Cockayne syndrome.
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We present a detailed mass spectrometric analysis of three 2 + 1 T-cell bispecific monoclonal antibodies (TCB mAbs), where an unexpected +15.9950 Da mass shift in tryptic peptides was observed. This modification was attributed to the occurrence of 5R-hydroxylysine (Hyl) using a hybrid LC-MS/MS molecular characterization and CRISPR/Cas9 gene deletion approach.

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A Phosphotriester-Masked Dideoxy-cGAMP Derivative as a Cell-Permeable STING Agonist.

Angew Chem Int Ed Engl

December 2024

Department of Chemistry, Institute for Chemical Epigenetics , Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377, Munich, Germany.

2',3'-Cyclic GMP-AMP (cGAMP) is a cyclic dinucleotide second messenger in which guanosine and adenosine are connected by one 3'-5' and one 2'-5' phosphodiester linkage. It is formed in the cytosol upon detection of pathogenic DNA by the enzyme guanosine-monophosphate-adenosine monophosphate synthase (cGAS). cGAMP subsequently binds to the adaptor protein stimulator of interferon genes (STING) to elicit an innate immune response leading to the production of type I interferons and cytokines.

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Article Synopsis
  • Metastatic disease is a major cause of cancer-related deaths, yet its tumor microenvironment is not well understood due to technical challenges in studying it.
  • This research created a comprehensive map of 67 tumor biopsies from 60 metastatic breast cancer patients, using advanced techniques like single-cell RNA sequencing and various spatial expression assays to analyze tumor characteristics.
  • Key findings included identifying different macrophage spatial patterns, three phenotypes of epithelial-to-mesenchymal transition, and gene expression linked to T cell presence or absence, highlighting the study's potential for clinical insights.
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Structural basis for human OGG1 processing 8-oxodGuo within nucleosome core particles.

Nat Commun

October 2024

State Key Laboratory of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, Department of Chemical Biology, College of Chemistry, Nankai University, Tianjin, 300071, China.

Base excision repair (BER) is initialized by DNA glycosylases, which recognize and flip damaged bases out of the DNA duplex into the enzymes active site, followed by cleavage of the glycosidic bond. Recent studies have revealed that all types of DNA glycosylases repair base lesions less efficiently within nucleosomes, and their repair activity is highly depended on the lesion's location within the nucleosome. To reveal the underlying molecular mechanism of this phenomenon, we determine the 3.

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Spatio-molecular data and microscopy images provide complementary information, essential to study structure and function of spatially organised multicellular systems such as healthy or diseased tissues. However, aligning these two types of data can be challenging due to distortions and differences in resolution, orientation, and position. Manual registration is tedious but may be necessary for challenging samples as well as for the generation of ground-truth data sets that enable benchmarking of existing and emerging automated alignment tools.

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Although many antibiotics inhibit bacterial ribosomes, loss of known factors that rescue stalled ribosomes does not lead to robust antibiotic sensitivity in , suggesting the existence of additional mechanisms. Here, we show that the RNA helicase HrpA rescues stalled ribosomes in Acting selectively on ribosomes that have collided, HrpA uses ATP hydrolysis to split stalled ribosomes into subunits. Cryo-EM structures reveal how HrpA simultaneously binds to two collided ribosomes, explaining its selectivity, and how its helicase module engages downstream mRNA, such that by exerting a pulling force on the mRNA, it would destabilize the stalled ribosome.

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Friendly fire: recognition of self by the innate immune system.

Curr Opin Immunol

October 2024

Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria. Electronic address:

The innate immune system employs two different strategies to detect pathogens: first, it recognizes microbial components as ligands of pattern recognition receptors (pattern-triggered immunity [PTI]), and second, it detects the activities of pathogen-encoded effectors (effector-triggered immunity [ETI]). Recently, these pathogen-centric concepts were expanded to include sensing of self-derived signals during cellular distress or damage (damage-triggered immunity [DTI]). This extension relied on broadening the PTI model to include damage-associated molecular patterns (DAMPs).

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Background: Deep learning has revolutionized medical image analysis in cancer pathology, where it had a substantial clinical impact by supporting the diagnosis and prognostic rating of cancer. Among the first available digital resources in the field of brain cancer is glioblastoma, the most common and fatal brain cancer. At the histologic level, glioblastoma is characterized by abundant phenotypic variability that is poorly linked with patient prognosis.

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DNA-sensing inflammasomes cause recurrent atherosclerotic stroke.

Nature

September 2024

Institute for Stroke and Dementia Research (ISD), LMU University Hospital, LMU Munich, Munich, Germany.

Article Synopsis
  • Research shows that despite current prevention methods, early recurrent strokes are still common, especially in patients with atherosclerosis, with over 10% experiencing repeat events.
  • A new mouse model revealed that strokes activate the AIM2 inflammasome in atherosclerotic plaques due to increased circulating cell-free DNA, leading to inflammation, plaque destabilization, and recurrent strokes.
  • Targeting the mechanisms of DNA-mediated inflammasome activation may offer new treatment options to reduce the high rate of recurrent strokes in at-risk patients.
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Inflammasomes are essential for host defense, recognizing foreign or stress signals to trigger immune responses, including maturation of IL-1 family cytokines and pyroptosis. Here, NLRP1 is emerging as an important sensor of viral infection in barrier tissues. NLRP1 is activated by various stimuli, including viral double-stranded (ds) RNA, ribotoxic stress, and inhibition of dipeptidyl peptidases 8 and 9 (DPP8/9).

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Innate immune responses are linked to key metabolic pathways, yet the proximal signaling events that connect these systems remain poorly understood. Here we show that phosphofructokinase 1, liver type (PFKL), a rate-limiting enzyme of glycolysis, is phosphorylated at Ser775 in macrophages following several innate stimuli. This phosphorylation increases the catalytic activity of PFKL, as shown by biochemical assays and glycolysis monitoring in cells expressing phosphorylation-defective PFKL variants.

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Engineered mammalian cells are key for biotechnology by enabling broad applications ranging from in vitro model systems to therapeutic biofactories. Engineered cell lines exist as a population containing sub-lineages of cell clones that exhibit substantial genetic and phenotypic heterogeneity. There is still a limited understanding of the source of this inter-clonal heterogeneity as well as its implications for biotechnological applications.

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A critical role for palmitoylation in pyroptosis.

Mol Cell

June 2024

Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität Munich, Butenandtstr. 1, 81377 Munich, Germany. Electronic address:

Three recent publications by Du et al., Balasubramanian et al., and Zhang et al.

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Article Synopsis
  • Decitabine (5-aza-dC) is a nucleoside analogue used for treating certain blood cancers, but its effectiveness can vary and relapses are common.
  • Research using CRISPR/Cas9 screens identified that the loss of the enzyme DCTD makes cancer cells resistant to decitabine by reducing the production of 5-aza-dUMP, which is toxic to cells.
  • The study revealed that the protein TOPORS helps repair decitabine-induced DNA damage and may be targeted for new biomarkers to predict how patients respond to decitabine treatment.
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Toll-like receptor 7 (TLR7) is essential for recognition of RNA viruses and initiation of antiviral immunity. TLR7 contains two ligand-binding pockets that recognize different RNA degradation products: pocket 1 recognizes guanosine, while pocket 2 coordinates pyrimidine-rich RNA fragments. We found that the endonuclease RNase T2, along with 5' exonucleases PLD3 and PLD4, collaboratively generate the ligands for TLR7.

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The major product of DNA-methylating agents, N7-methyl-2'-deoxyguanosine (MdG), is a persistent lesion , but it is not believed to have a large direct physiological impact. However, MdG reacts with histone proteins to form reversible DNA-protein cross-links (DPC), a family of DNA lesions that can significantly threaten cell survival. In this paper, we developed a tandem mass spectrometry method for quantifying the amounts of MdG and DPC in nuclear DNA by taking advantage of their chemical lability and the concurrent release of N7-methylguanine.

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Article Synopsis
  • Covalent DNA-protein cross-links (DPCs) are harmful lesions that stall DNA replication and need various repair mechanisms, including their impact on transcription.
  • The study reveals that DPCs hinder transcription and trigger the degradation of RNA polymerase II, with Cockayne syndrome (CS) proteins CSB and CSA helping to repair these lesions in transcribed genes.
  • CSB and CSA deficiencies result in transcriptional restart issues post-DPC induction, whereas certain nucleotide excision repair factors are not essential, indicating a specific transcription-coupled DPC repair pathway that may explain neurological symptoms in Cockayne syndrome.
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Article Synopsis
  • - This study examined risk and protective factors for COVID-19 among healthcare workers (HCWs) in Munich, focusing on occupational risks and non-occupational influences.
  • - Out of 3,696 vaccinated HCWs, 6.6% had COVID-19, with patient care occupations, community contact with COVID cases, obesity, and frequent travel identified as significant risk factors, while early vaccination, smoking, living with elderly family members, and eating ready-to-eat meals were associated with lower infection rates.
  • - The findings suggest that understanding the interplay between living conditions, travel habits, and dietary choices can help improve measures for protecting vulnerable populations from COVID-19.
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Mechanisms of Translation-coupled Quality Control.

J Mol Biol

March 2024

Gene Center and Department of Biochemistry, Feodor-Lynen-Str. 25, University of Munich, 81377 Munich, Germany. Electronic address:

Stalling of ribosomes engaged in protein synthesis can lead to significant defects in the function of newly synthesized proteins and thereby impair protein homeostasis. Consequently, partially synthesized polypeptides resulting from translation stalling are recognized and eliminated by several quality control mechanisms. First, if translation elongation reactions are halted prematurely, a quality control mechanism called ribosome-associated quality control (RQC) initiates the ubiquitination of the nascent polypeptide chain and subsequent proteasomal degradation.

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Increased nuclear size correlates with lower survival rates and higher grades for prostate cancer. The short-chain dehydrogenase/reductase (SDR) family member DHRS7 was suggested as a biomarker for use in prostate cancer grading because it is largely lost in higher-grade tumors. Here, we found that reduction in DHRS7 from the LNCaP prostate cancer cell line with normally high levels of DHRS7 increases nuclear size, potentially explaining the nuclear size increase observed in higher-grade prostate tumors where it is lost.

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Stalled ribosomes are rescued by pathways that recycle the ribosome and target the nascent polypeptide for degradation. In E. coli, these pathways are triggered by ribosome collisions through the recruitment of SmrB, a nuclease that cleaves the mRNA.

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