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Hypoxia can induce the reactivation of Kaposi sarcoma-associated virus (KSHV), which necessitates the synthesis of critical structural proteins. Despite the unfavorable energetic conditions of hypoxia, KSHV utilizes mechanisms to prevent the degradation of essential cellular machinery required for successful reactivation. Our study provides new insights on strategies employed by KSHV-infected cells to maintain steady-state transcription by overcoming hypoxia-mediated metabolic stress to enable successful reactivation. Our discovery that the interaction of latency-associated nuclear antigen with HIF1α and NEDD4 inhibits its polyubiquitination activity, which blocks the degradation of RNA Pol II during hypoxia, is a significant contribution to our understanding of KSHV biology. This newfound knowledge provides new leads in the development of novel therapies for KSHV-associated diseases.
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http://dx.doi.org/10.1128/mbio.02774-23 | DOI Listing |
Am J Hum Genet
September 2025
Department of Clinical Genetics, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, Rotterdam 3000 CA, the Netherlands.
Microtubule-actin cross-linking factor 1 (MACF1) is a large protein of the spectraplakin family, which is essential for brain development. MACF1 interacts with microtubules through the growth arrest-specific 2 (Gas2)-related (GAR) domain. Heterozygous MACF1 missense variants affecting the zinc-binding residues in this domain result in a distinctive cortical and brain stem malformation.
View Article and Find Full Text PDFBiochem J
September 2025
Cancer Research UK Scotland Institute, Glasgow, G61 1BD, U.K.
RNA cap formation on RNA polymerase II transcripts is regulated by cellular signalling pathways during development and differentiation, adaptive and innate immune responses, during the cell cycle and in response to oncogene deregulation. Here, we discuss how the RNA cap methyltransferase, RNA guanine-7 methyltransferase (RNMT), functions to complete the 7-methyl-guanosine or m7G cap. The mechanisms by which RNMT is regulated by signalling pathways, co-factors and other enzymes are explored.
View Article and Find Full Text PDFNAR Genom Bioinform
September 2025
Department of Internal Medicine, Nephrology Division, University of Michigan, Ann Arbor 48109 MI, United States.
The dynamics of transcriptional elongation influence many biological activities, such as RNA splicing, polyadenylation, and nuclear export. To quantify the elongation rate, a typical method is to treat cells with drugs that inhibit RNA polymerase II (Pol II) from entering the gene body and then track Pol II using Pro-seq or Gro-seq. However, the downstream data analysis is challenged by the problem of identifying the transition point between the gene regions inhibited by the drug and not, which is necessary to calculate the transcription rate.
View Article and Find Full Text PDFHIV-1 particle assembly depends critically on multiple proteolytic cleavages of viral polyproteins by the viral protease, PR. PR is translated as part of the Gag-Pro-Pol polyprotein, which undergoes autoproteolysis to liberate active, dimeric PR during virus particle maturation. Gag-Pro-Pol is produced via an infrequent -1 frameshifting event in ribosomes translating full length genomic RNA as Gag mRNA.
View Article and Find Full Text PDFTranscription elongation by RNA polymerase II is a tightly regulated process that requires coordinated interactions between elongation factors. IWS1 (Interacts with SPT6) has been implicated as a core elongation factor, but its molecular role remains unclear. We show that the intrinsically disordered C-terminal region of IWS1 contains short linear motifs (SLiMs) that multivalently engage the elongation machinery.
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