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The SARS-CoV-2 genome has been shown to be mA methylated at several positions in vivo. Strikingly, a DRACH motif, the recognition motif for adenosine methylation, resides in the core of the transcriptional regulatory leader sequence (TRS-L) at position A74, which is highly conserved and essential for viral discontinuous transcription. Methylation at position A74 correlates with viral pathogenicity. Discontinuous transcription produces a set of subgenomic mRNAs that function as templates for translation of all structural and accessory proteins. A74 is base-paired in the short stem-loop structure 5'SL3 that opens during discontinuous transcription to form long-range RNA-RNA interactions with nascent (-)-strand transcripts at complementary TRS-body sequences. A74 can be methylated by the human METTL3/METTL14 complex in vitro. Here, we investigate its impact on the structural stability of 5'SL3 and the long-range TRS-leader:TRS-body duplex formation necessary for synthesis of subgenomic mRNAs of all four viral structural proteins. Methylation uniformly destabilizes 5'SL3 and long-range duplexes and alters their relative equilibrium populations, suggesting that the mA74 modification acts as a regulator for the abundance of viral structural proteins due to this destabilization.
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http://dx.doi.org/10.1002/chem.202401897 | DOI Listing |
Dev Dyn
September 2025
Department of Internal Medicine, Division of Cardiovascular Medicine, Francois M. Abboud Cardiovascular Research Center, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA.
Background: Gene transcription is crucial for embryo and postnatal development and is regulated by the Mediator complex. Mediator is comprised of four submodules, including the kinase submodule (CKM). The CKM consists of MED13, MED12, CDK8, and CCNC.
View Article and Find Full Text PDFFront Immunol
September 2025
Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming, Yunnan, China.
Subgenomic RNAs (sgRNAs) are discontinuous transcription products of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that are involved in viral gene expression and replication, but their exact functions are still being studied. Here, we report the identification of a nested ORF3a-sgRNA, the fusion ORF3a-E-sgRNA, which is involved in the infection process of SARS-CoV-2. This sgRNA encodes both ORF3a and E and can be detected throughout the viral life cycle in SARS-CoV-2-infected cells with high copy numbers.
View Article and Find Full Text PDFRNA G-quadruplexes (rG4s) are unusual RNA secondary structures formed by stacking arrays of guanine tetrads. Although thousands of potential rG4-forming motifs occur throughout the mammalian transcriptome, many single-stranded RNA (ssRNA) viruses are thought to be depleted of rG4-forming sequences. Using in silico methods, we examine rG4-forming potential in single-stranded RNA (ssRNA) viruses and observe that, while canonical rG4 motifs are depleted, non-canonical rG4 motifs occur at comparable or higher frequencies relative to the mammalian transcriptome.
View Article and Find Full Text PDFPerspect Med Educ
August 2025
Education Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands.
Introduction: Clinician-teachers are engaged in both clinical practice and education. They positively influence student learning by connecting clinical practice and education. Most research into clinician-teacher's dual role was performed in the clinical settings where practice and teaching are intertwined.
View Article and Find Full Text PDFJ Shoulder Elbow Surg
July 2025
Department of Orthopaedic Surgery, Geelong University Hospital, Geelong, Australia; Barwon Centre for Orthopaedic Research and Education (BCORE), St John of God and Geelong University Hospitals, Geelong, Australia; IMPACT - The Institute for Mental and Physical Health and Clinical Translation, Barwo
Background: Rotator cuff tears are a leading cause of shoulder pain and dysfunction, with variable healing after rotator cuff repair. Predicting tendon healing remains challenging, with failure rates reaching 21% at 2 years. This study employs transcriptomic analysis to identify gene pathways associated with tendon healing, with clinical and radiological correlation at 2 years postoperatively.
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