Search PubMed⌕ Search
Home/Archive/PubMed

PubMed · 39804127

Modulation of Cell Cycle Kinases by Kaposi's Sarcoma-Associated Herpesvirus.

Steven Longworth·Blossom Damania
View original source ↗Export metadata ↓

Abstract

The cell cycle is governed by kinase activity that coordinates progression through a series of regulatory checkpoints, preventing the division of damaged cells. The Kaposi's sarcoma-associated herpesvirus (KSHV) encodes multiple genes that modulate or co-opt the activity of these kinases, shaping the cellular environment to promote viral persistence. By advancing the cell cycle, KSHV facilitates latent replication and subsequent transmission of viral genomes to daughter cells, while also contributing to the establishment of multiple cancer types. Conversely, during viral lytic replication, KSHV extends the resting phase of the cell cycle to prevent cellular DNA synthesis that would otherwise compete for essential replication precursors. This review will examine the mechanisms KSHV has evolved to control the kinase activity regulating host cell cycle progression.

Explore related subjects

Herpesvirus 8, HumanHumansVirus ReplicationCell CycleVirus LatencyHost-Pathogen InteractionsSarcoma, KaposiPhosphotransferasescell cyclehuman herpesvirus 8 (Kaposi sarcoma‐associated herpesvirus)signal transductionJournal ArticleReviewResearch Support, N.I.H., Extramural

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Steven Longworth, Blossom Damania. 2025. Modulation of Cell Cycle Kinases by Kaposi's Sarcoma-Associated Herpesvirus.. https://doi.org/10.1002/jmv.70157

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2025

Characterization of the Kaposi's sarcoma-associated herpesvirus terminase complex component ORF29.

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). The herpesvirus terminase complex packages a single genomic unit into a capsid by cleaving the TRs in the precursor genome. Although the terminase complexes of alpha- and beta-herpesviruses are well characterized, the KSHV terminase complex is poorly understood. KSHV ORF7, ORF67.5, and ORF29 are thought to be components of this complex. We previously reported that KSHV deficient in either ORF7 or ORF67.5 formed immature, soccer ball-like capsids and failed to cleave the TRs, resulting in decreased virion production. Moreover, ORF7 interacted with both ORF29 and ORF67.5; however, ORF29 and ORF67.5 did not interact with each other. Thus, although ORF7 and ORF67.5 are important for KSHV terminase function, the function of ORF29 remains largely unknown. In this study, we constructed an ORF29-deficient KSHV and analyzed its virological properties. ORF29 was found to be essential for virion production and TR cleavage. Numerous immature, soccer ball-like capsids were observed in cells harboring ORF29-deficient KSHV. The N-terminal region of ORF29 was important for its interaction with ORF7, although the full-length ORF29 was required for effective assembly of the KSHV terminase complex. Furthermore, ORF29 preferentially interacted with itself rather than with ORF7. Thus, our data show that ORF29 functions as a fundamental component of the terminase complex.IMPORTANCEBecause the role of ORF29 in the Kaposi's sarcoma-associated herpesvirus (KSHV) terminase complex remains unknown, we constructed ORF29-deficient KSHV. Our results demonstrated that ORF29 functions as a component of the KSHV terminase and is essential for mature capsid formation, terminal repeat (TR) cleavage, and terminase complex assembly. Moreover, ORF29 strongly interacted with itself. In herpes simplex virus 1 (HSV-1), the terminase complex (comprising UL15, UL28, and UL33) forms a trimer, and six such trimers assemble into a hexameric ring. The HSV-1 genome passes through this ring and undergoes TR cleavage and genome packaging into a capsid. The self-interaction of ORF29 may be involved in the multimerization of the terminase complex or in the formation of the KSHV terminase ring.

Herpesvirus 8, Human↗
PubMed2025

The elevated expression of ORF75, a KSHV lytic gene, in Kaposi sarcoma lesions is driven by a GC-rich DNA cis element in its promoter region.

The spindle cells of Kaposi sarcoma (KS) lesions primarily express Kaposi sarcoma herpesvirus (KSHV) latent genes with minimal expression of lytic genes. However, recent transcriptome analyses of KS lesions have shown high expression of KSHV open reading frame (ORF) 75, which is considered a late lytic gene based on analyses in primary effusion lymphoma (PEL) lines. ORF75 encodes a pseudo-amidotransferase that is part of the viral tegument, acts as a suppressor of innate immunity, and is essential for viral lytic replication. We assessed a representative KS lesion by RNAscope and found that ORF75 RNA was expressed in the majority of latency-associated nuclear antigen (LANA)-expressing cells. Luciferase fusion reporter constructs of the ORF75 promoter were analyzed for factors potentially driving its expression in KS. The ORF75 promoter construct showed high basal transcriptional activity in vitro in endothelial cells, mediated by a proximal consensus specificity protein 1 (Sp1) (GGGGCGGGGC) element along with two distal CCAAT boxes. Sp proteins formed complexes with the proximal consensus Sp1 element to activate ORF75 promoter transcription. We also found evidence that a repressive factor or factors in B cells, but not endothelial or epithelial cells, interacted with more distal elements in the ORF75 promoter region to repress constitutive ORF75 expression in B cells. Alternate forms of Sp1 were found to accumulate during latency and showed substantial enrichment during viral lytic replication in PEL cells and infected endothelial cells, but their functional significance is unclear. We also found that ORF75 can in turn upregulate its own expression and that of other KSHV genes. Thus, while ORF75 acts primarily as a lytic gene in PEL cell lines, Sp proteins induce substantial constitutive ORF75 transcription in infected endothelial cells and this can account for its high expression in KS lesions.

Herpesvirus 8, Human↗
PubMed2025

KSHVbook: An Information-Sharing Database for Kaposi's Sarcoma-Associated Herpesvirus.

Kaposi's sarcoma-associated herpesvirus (KSHV) is a double-stranded DNA virus belonging to the γ-herpesvirus subfamily. KSHV is the causative agent of Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), multicentric Castleman's disease (MCD), and KSHV inflammatory cytokine syndrome (KICS). Since its discovery, research on KSHV has rapidly progressed, but existing information platforms relatively lack comprehensiveness and do not provide efficient analysis tools tailored for KSHV. To further promote the research on KSHV more effectively, we have developed KSHVbook (http://www.kshvbook.com), a specialized information-sharing database dedicated to KSHV. This platform offers extensive information on genes, coding sequences, proteins, and the gene regulatory region. Besides, the KSHVbook includes about 35 010 transcription factor binding sites (TFBSs), 342 010 pairs of KSHV miRNA-host target gene relationships, protein structures predicted by AlphaFold3, qPCR primers, and so on. We also develop analytical tools for viral genome regions, TFBSs, and KSHV miRNA target genes to discover previously unknown biological functions of KSHV. These analytical tools can effectively identify the potential regulatory relationships between host transcription factors and viral genes. Overall, this platform provides a centralized data resource for KSHV research by integrating multiple databases, offering accessible analysis tools, and simplifying data acquisition. The KSHVbook will continue to be updated, and more features can be found on the website.

Herpesvirus 8, Human↗