The exosome is the major 3'-5' RNA-degradation complex in eukaryotes. The ubiquitous core of the yeast exosome (Exo-10) is formed by nine catalytically inert subunits (Exo-9) and a single active RNase, Rrp44. In the nucleus, the Exo-10 core recruits another nuclease, Rrp6. Here we crystallized an approximately 440-kilodalton complex of Saccharomyces cerevisiae Exo-10 bound to a carboxy-terminal region of Rrp6 and to an RNA duplex with a 3'-overhang of 31 ribonucleotides. The 2.8 Å resolution structure shows how RNA is funnelled into the Exo-9 channel in a single-stranded conformation by an unwinding pore. Rrp44 adopts a closed conformation and captures the RNA 3'-end that exits from the side of Exo-9. Exo-9 subunits bind RNA with sequence-unspecific interactions reminiscent of archaeal exosomes. The substrate binding and channelling mechanisms of 3'-5' RNA degradation complexes are conserved in all kingdoms of life.
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http://dx.doi.org/10.1038/nature11870 | DOI Listing |
J Vis Exp
January 2025
Institute of Biochemistry and Molecular Biology, Hengyang Medical School, University of South China; National Health Commission Key Laboratory of Birth Defect Research and Preventio, Hunan Provincial Maternal and Child Health Care Hospital;
Both DNA replication and RNA transcription utilize genomic DNA as their template, necessitating spatial and temporal separation of these processes. Conflicts between the replication and transcription machinery, termed transcription-replication conflicts (TRCs), pose a considerable risk to genome stability, a critical factor in cancer development. While several factors regulating these collisions have been identified, pinpointing primary causes remains difficult due to limited tools for direct visualization and clear interpretation.
View Article and Find Full Text PDFBioinformatics
January 2025
School of Computing and Artificial Intelligence, Southwest Jiaotong University, Sichuan 611756, China.
Motivation: The rapid development of single-cell RNA sequencing (scRNA-seq) has significantly advanced biomedical research. Clustering analysis, crucial for scRNA-seq data, faces challenges including data sparsity, high dimensionality, and variable gene expressions. Better low-dimensional embeddings for these complex data should maintain intrinsic information while making similar data close and dissimilar data distant.
View Article and Find Full Text PDFAppl Microbiol Biotechnol
January 2025
Chair of Microbiology, Technical University of Munich, TUM School of Life Science, Emil-Ramann-Str. 4, 85354, Freising, Germany.
The anaerobic bacterium Clostridium cellulovorans is a promising candidate for the sustainable production of biofuels and platform chemicals due to its cellulolytic properties. However, the genomic engineering of the species is hampered because of its poor genetic accessibility and the lack of genetic tools. To overcome this limitation, a protocol for triparental conjugation was established that enables the reliable transfer of vectors for markerless chromosomal modification into C.
View Article and Find Full Text PDFJ Cancer Res Clin Oncol
January 2025
Key Laboratory of Laboratory Medicine, Ministry of Education of China, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China.
Purpose: Growing evidence suggests that the tyrosine phosphatase SHP2 is pivotal for tumor progression. Triple-negative breast cancer (TNBC) is the most lethal subtype of breast cancer, characterized by its high recurrence rate, aggressive metastasis, and resistance to chemotherapy. Understanding the mechanisms of tumorigenesis and the underlying molecular pathways in TNBC could aid in identifying new therapeutic targets.
View Article and Find Full Text PDFInt J Syst Evol Microbiol
January 2025
Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, Republic of Korea.
Strain NoAH (=KACC 23135=JCM 35999), a novel Gram-negative, motile bacterium with a rod-shaped morphology, was isolated from the zoo animal faecal samples, specifically the long-tailed goral species . The novel bacterial strain grew optimally in a nutrient broth medium under the following conditions: 1-2% (w/v) NaCl, pH 7-8 and 30 °C. The strain NoAH exhibited high tolerance to NaCl, with the ability to tolerate up to 7% (w/v) NaCl.
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