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The epitranscriptomic modification -methyladenosine (mA) is a ubiquitous feature of the mammalian transcriptome. It modulates mRNA fate and dynamics to exert regulatory control over numerous cellular processes and disease pathways, including viral infection. Kaposi's sarcoma-associated herpesvirus (KSHV) reactivation from the latent phase leads to the redistribution of mA topology upon both viral and cellular mRNAs within infected cells. Here we investigate the role of mA in cellular transcripts upregulated during KSHV lytic replication. Our results show that mA is crucial for the stability of the mRNA, whose expression is induced by the KSHV latent-lytic switch master regulator, the replication and transcription activator (RTA) protein. Moreover, we demonstrate that GPRC5A is essential for efficient KSHV lytic replication by directly regulating NFκB signalling. Overall, this work highlights the central importance of mA in modulating cellular gene expression to influence viral infection.
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http://dx.doi.org/10.3390/v15061381 | DOI Listing |
Microbiol Spectr
September 2025
Department of Cell Biology, Kyoto Pharmaceutical University, Kyoto, Japan.
Kaposi's sarcoma-associated herpesvirus (KSHV) belongs to the Gammaherpesvirinae subfamily. During the lytic phase of herpesviruses, viral capsids form in the host cell nucleus, and the replicated viral genome is packaged into these capsids. The herpesviral genome is replicated as a precursor head-to-tail concatemer consisting of tandemly repeated genomic units, each flanked by terminal repeats (TRs).
View Article and Find Full Text PDFUnlabelled: Kaposi's sarcoma-associated herpesvirus (KSHV) orchestrates late gene transcription through viral transcriptional activators that hijack host RNA polymerase II machinery, maintaining selectivity for viral promoters. Among these, the KSHV protein ORF24 serves as a TATA-binding protein (TBP) mimic essential for recognizing viral late promoters, although the molecular mechanisms underlying its function remain poorly characterized. Here, we used AlphaFold3 to predict the structure of ORF24 in complex with DNA and validated key features in both transfected cells and during KSHV lytic replication.
View Article and Find Full Text PDFJ Vis Exp
August 2025
Program in Molecular and Cellular Oncogenesis, The Wistar Institute;
Kaposi's sarcoma-associated herpesvirus (KSHV), a gammaherpesvirus implicated in multiple human malignancies, can undergo lytic replication during primary infection, a process that contributes to viral dissemination, immune evasion, and disease pathogenesis. However, the lack of robust in vitro systems for de novo lytic infection has limited insights into early infection events. Here, we present a tractable protocol that employs human colorectal cancer HCT 116 cells as targets for infection with cell-free virions derived from KSHV bacterial artificial chromosome 16 (BAC16)-reactivated iSLK producer cells.
View Article and Find Full Text PDFJ Virol
August 2025
HIV and AIDS Malignancy Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA.
Viral infections lead to caspase activation as a cellular defense response. Some viruses overcome this response by encoding viral proteins that undergo caspase cleavage and, by various mechanisms, aid in cell survival. Kaposi sarcoma-associated herpesvirus (KSHV) latency-associated nuclear antigen acts as a pseudo-substrate for caspases-1 and -3, thereby interfering with the inflammatory and apoptotic response.
View Article and Find Full Text PDFVirology
October 2025
International Centre for Genetic Engineering and Biotechnology (ICGEB), Cape Town 7925, South Africa; Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa; Division of Medical Biochemistry and Structural Biol
Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) are oncogenic human γ-herpesviruses highly prevalent in Sub-Saharan Africa. Both establish latent early-life infections, with intermittent lytic reactivations, often triggered by viral co-infections, particularly in immunocompromised individuals. In this retrospective observational cross-sectional sub-study, we leveraged a cohort of 407 non-hospitalised people living with HIV (PLWH) attending antiretroviral therapy services in South Africa during the COVID-19 pandemic, with previously reported increased reactivation of KSHV upon SARS-CoV-2 exposure, particularly in COVID-19 unvaccinated individuals (Lambarey et al.
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