Viral Integration Research Articles

DDDR-42. LEVERAGING GENOME-WIDE CRISPR/CAS9 KNOCKOUT DRUG SCREENS TO IDENTIFY SENSITIZERS FOR PROTEOSOME INHIBITORS IN GLIOBLASTOMA

Abstract Glioblastoma (GBM) is the most common primary brain tumor with a poor prognosis despite aggressive treatment. Patient outcomes remain abysmal with 95% of patients relapsing and a median overall survival of 15 months. This necessitates the rapid search for personalized therapeutics and agents to enhance current treatments. One pathway that demonstrates dysregulated functioning is the ubiquitin-proteasome pathway (UPP). Literature has shown that UPP dependent proteolysis remains constitutively upregulated in cancer cells leading to the rapid degradation of proteins that regulate oncogenic pathways. Despite robust preclinical evaluations for the usage of proteasome inhibitors against GBM, most proteasome inhibitors failed in clinical trials, indicating resistance. We conducted an unbiased genome wide CRISPR-Cas9 screen in HAP1 cells treated with the proteasome inhibitor, Bortezomib (BTZ), to identify genes leading to a BTZ-resistant phenotype. We identified several genes that when perturbed, sensitized cells to BTZ including N-glycanase-1 (NGLY-1), Nuclear factor Erythroid 2-Like-1 (NFE2L1), and DNA damage inducible 1 homolog 2 (DDI2). Herein, we sought to evaluate the effects of perturbing these identified genes in our patient derived GBM cell lines by utilizing CRISPR/Cas9 knockout technology in vitro and in vivo. The generation of NGLY-1, DDI2, and NFE2L1 KO cell lines demonstrated functional sensitivity to the proteasome inhibitor Marizomib (MZB) as observed through a significant reduction of the IC50 in the KO cell lines compared to an adeno-associated virus integration site 1 (AAVS1) control. Functional evaluation also demonstrated reduced proliferation capacity and sphere formation in our KO GBM lines. Ongoing in vivo work will aim to evaluate the mitigation of this resistant pathway in our NSG mouse models orthotopically transplanted with our patient derived KO cell lines. In an ongoing collaborative effort, we aim to functionally assess a novel small molecule NGLY-1 inhibitor for preclinical sensitivity to MZB in our in vitro and in vivo models.

Molecular Pathogenesis of Human Papillomavirus: Insights into Viral Oncoproteins and Host Integration

Human Papillomavirus (HPV) is a major cause of death from cervical cancer and other anogenital cancers throughout the world. Pathogenicity of HPV is governed by intricate interplay of HPV and host cells mediated primarily by its oncoproteins E6 and E7. These oncoproteins disrupt critical pathways, including those involving tumor suppressors p53 and retinoblastoma (Rb) to induce unregulated cell proliferation and evasion of apoptosis. These mechanisms have been studied in order to develop the different diagnostic tools, such as HPV DNA testing and genotyping, and there are emerging techniques based on E6/E7 mRNA detection and high throughput sequencing. In addition, therapeutic strategies have advanced with the vaccines showing ability to prevent high risk HPV infection and ongoing research to developing targeted therapies to disrupt viral oncoprotein function. New diagnostic and therapeutic approaches to HPV research encompassing an expanding clinical landscape hold promise to reduce incidence of HPV associated malignancies and improve patient outcomes. This review summarizes the molecular pathogenesis of HPV with respect to host cells and discusses its implications for diagnostics and therapeutics, including the need for further development in this area.

Genome Instability Precedes Viral Integration in Human Papilloma Virus Transformed Tonsillar Keratinocytes.

Approximately 70% of oropharyngeal squamous carcinomas (OPSCC) are associated with human papillomavirus (HPV). While patients with HPV-positive tumors generally have better outcomes than those with HPV-negative tumors, a subset of HPV-positive patients do have poor outcomes. Our previous work suggested that tumors with integrated virus exhibit significantly greater genome wide genomic instability than those with only episomal viral genomes and patients with HPV+ OPSCC with episomal viral genomes had better outcomes. To explore the causal relation between viral integration and genomic instability, we have examined the time course of viral integration and genetic instability in tonsillar keratinocytes transformed with HPV16. HPV-infected human tonsil keratinocyte cell lines were continuously passaged and every fifth passage some cells were retained for genomic analysis. Whole genome sequencing and optical genomic mapping confirmed that virus integrated in five of six cell lines while remaining episomal in the sixth. In all lines genome instability occurred during early passages, but essentially ceased following viral integration but continued to occur later passages in the episomal line. To test tumorigenicity of the cell lines, cells were injected subcutaneously into the flanks of nude mice. A cell line with the integrated virus induced tumors following injection in the nude mouse while that with the episomal virus did not. Implications: Genomic instability in HPV OPSCC tumors is not the result of viral integration but likely promotes integration. Moreover, transformants with episomal virus appear to be less tumorigenic than those with integrated virus.

A case of squamous cell carcinoma of the lung misdiagnosed as tuberculosis. Is HPV infected by oral sex the causative agent?

BackgroundThe integration of high-risk human papilloma virus (HPV) DNA into the human genome has been implicated in cervical carcinogenesis and head and neck squamous cell cancer. However, its role in lung squamous cell carcinoma is not well understood. In addition, tuberculosis (TB) and lung cancer(LC) share similar clinical symptoms and imaging features, increasing the risk of misdiagnosis.Case PresentationThe patient presented with a 16-month history of hemoptysis, chest pain, and occasional fatigue, without fever, chills, or history of mechanical damage or autoimmune diseases. Examination revealed normal vital signs and laboratory parameters, except for a positive interferon-gamma release assay indicating tuberculosis infection. Bronchoscopic examinations identified congestion and edema of the tracheal wall, along with a tiny lesion in the right wall of the trachea. She had been misdiagnosed with tuberculosis. However, the diagnosis of squamous cell carcinoma was eventually confirmed by endoscopic biopsy. The patient’s macrogenomic second-generation sequencing (mNGS) of the bronchoscopic biopsy specimen was positive for HPV-16.The patient’s sex partner tested positive for HPV-16 in penile scrapings, indicating HPV transmission through oral sex.ConclusionsThis case highlights the potential for HPV infection acquired through oral sex to lead to lung squamous cell carcinoma. It emphasizes the importance of considering HPV-associated malignancies in patients with respiratory symptoms who engage in oral sexual behaviors.

Towards the genomic sequence code of DNA fragility for machine learning.

Genomic DNA breakages and the subsequent insertion and deletion mutations are important contributors to genome instability and linked diseases. Unlike the research in point mutations, the relationship between DNA sequence context and the propensity for strand breaks remains elusive. Here, by analyzing the differences and commonalities across myriads of genomic breakage datasets, we extract the sequence-linked rules and patterns behind DNA fragility. We show the overall deconvolution of the sequence influence into short-, mid- and long-range effects, and the stressor-dependent differences in defining the range and compositional effects on DNA fragility. We summarize and release our feature compendium as a library that can be seamlessly incorporated into genomic machine learning procedures, where DNA fragility is of concern, and train a generalized DNA fragility model on cancer-associated breakages. Structural variants (SVs) tend to stabilize regions in which they emerge, with the effect most pronounced for pathogenic SVs. In contrast, the effects of chromothripsis are seen across regions less prone to breakages. We find that viral integration may bring genome fragility, particularly for cancer-associated viruses. Overall, this work offers novel insights into the genomic sequence basis of DNA fragility and presents a powerful machine learning resource to further enhance our understanding of genome (in)stability and evolution.

Deep mining reveals the diversity of endogenous viral elements in vertebrate genomes

Integration of viruses into host genomes can give rise to endogenous viral elements (EVEs), which provide insights into viral diversity, host range and evolution. A systematic search for EVEs is becoming computationally challenging given the available genomic data. We used a cloud-computing approach to perform a comprehensive search for EVEs in the kingdoms Shotokuvirae and Orthornavirae across vertebrates. We identified 2,040 EVEs in 295 vertebrate genomes and provide evidence for EVEs belonging to the families Chuviridae, Paramyxoviridae, Nairoviridae and Benyviridae. We also find an EVE from the Hepacivirus genus of flaviviruses with orthology across murine rodents. In addition, our analyses revealed that reptarenaviruses and filoviruses probably acquired their glycoprotein ectodomains three times independently from retroviral elements. Taken together, these findings encourage the addition of 4 virus families and the Hepacivirus genus to the growing virus fossil record of vertebrates, providing key insights into their natural history and evolution.

Regulation of expression of unintegrated and integrated HIV-1 DNA: keeping the wolves at bay

The unintegrated HIV-1 DNAs formed by reverse transcription in the early hours after infection are subject to profound transcriptional silencing. The repression of expression of foreign DNA, as an aspect of the innate immune system, serves to restrict the activity of many invading pathogens. Newly formed retroviral DNAs are rapidly loaded with histones upon entry into the nucleus, and the repression of their expression is mediated by an array of host proteins that introduce histone modifications characteristic of heterochromatin, including histone methylation and histone deacetylation. Knockout or knockdown of expression or inhibition of these host factors can relieve the silencing, allowing for viral gene expression even in settings where HIV-1 DNA integration is blocked. When viral DNA integration is allowed, forming the integrated provirus, the silencing in most cases is dramatically relieved, leading to high levels of expression and formation of progeny virus. In some settings and cell types, silencing of the integrated DNA is maintained, or re-established, such that the infected cells retain a silent copy of the viral DNA without production of progeny virus. The basis for the typical switch from silent DNA to actively expressed DNA upon integration is not yet fully clear. This review will summarize the current understanding of the regulation of expression of unintegrated HIV-1 DNAs and the nature of the chromatin that is formed on the viral DNA, and will especially focus on the host machinery that establishes repressive heterochromatin-like structures on the unintegrated DNA. The activation of expression that normally occurs upon integration, and the special circumstances when viral DNA expression is not activated, will also be discussed. These cases can result in the formation of populations of infected cells carrying silent proviruses, which persist for decades in infected individuals in spite of antiviral therapy. This pool of latently infected cells can be stochastically reactivated to give rise to spreading virus whenever antiviral drugs are withdrawn, and constitute the barrier to a true “cure” of AIDS. The hope is that a deeper understanding of the regulation of expression of viral DNAs will lead to new means to prevent or control viremia and disease.

Intra-host genomic diversity and integration landscape of human tissue-resident DNA virome.

The viral intra-host genetic diversitiesand interactions with the human genome during decades of persistence remain poorly characterized. In this study, we analyzed the variability and integration sites of persisting viruses in nine organs from thirteen individuals who died suddenly from non-viralcauses. The viruses studiedincluded parvovirus B19, six herpesviruses, Merkel cell (MCPyV) and JC polyomaviruses, totaling 127 genomes. The viral sequences across organs were remarkably conserved within each individual, suggesting that persistence stems from single dominant strains. This indicates that intra-host viral evolution, thus far inferred primarily from immunocompromised patients, is likely overestimated in healthy subjects. Indeed, we detected increased viral subpopulations in two individuals with putative reactivations, suggesting that replication status influences diversity. Furthermore, we identified asymmetrical mutationpatternsreflectingselective pressures exerted by the host. Strikingly, our analysis revealed non-clonal viral integrations even in individuals without cancer. These included MCPyV integrations and truncations resembling clonally expanded variants inMerkel cell carcinomas, as well as novel junctions between herpesvirus 6B and mitochondrial sequences, the significance of which remains to be evaluated. Our work systematically characterizes the genomic landscape of the tissue-resident virome, highlighting potential deviations occurring during disease.

HPV16 integration regulates ferroptosis resistance via the c-Myc/miR-142-5p/HOXA5/SLC7A11 axis during cervical carcinogenesis

BackgroundFerroptosis, a newly identified form of regulated cell death triggered by small molecules or specific conditions, plays a significant role in virus-associated carcinogenesis. However, whether tumours arising after high-risk HPV integration are associated with ferroptosis is unexplored and remains enigmatic.MethodsHigh-risk HPV16 integration was analysed by high­throughput viral integration detection (HIVID). Ferroptosis was induced by erastin, and the levels of ferroptosis were assessed through the measurement of lipid-reactive oxygen species (ROS), malondialdehyde (MDA), intracellular Fe2+ level and transmission electron microscopy (TEM). Additionally, clinical cervical specimens and an in vivo xenograft model were utilized for the study.ResultsExpression of HPV16 integration hot spot c-Myc negatively correlates with ferroptosis during the progression of cervical squamous cell carcinoma (CSCC). Further investigation revealed that the upregulated oncogene miR-142-5p in HPV16-integrated CSCC cells served as a critical downstream effector of c-Myc in its target network. Inhibiting miR-142-5p significantly decreased the ferroptosis-suppressing effect mediated by c-Myc. Through a combination of computational and experimental approaches, HOXA5 was identified as a key downstream target gene of miR-142-5p. Overexpression of miR-142-5p suppressed HOXA5 expression, leading to decreased accumulation of intracellular Fe2+ and lipid peroxides (ROS and MDA). HOXA5 increased the sensitivity of CSCC cells to erastin-induced ferroptosis via transcriptional downregulation of SLC7A11, a negative regulator of ferroptosis. Importantly, c-Myc knockdown increased the anti-tumour activity of erastin by promoting ferroptosis both in vitro and in vivo.ConclusionsCollectively, these data indicate that HPV16 integration hot spot c-Myc plays a novel and indispensable role in ferroptosis resistance by regulating the miR-142-5p/HOXA5/SLC7A11 signalling axis and suggest a potential therapeutic approach for HPV16 integration-related CSCC.

Long-read sequencing of an advanced cancer cohort resolves rearrangements, unravels haplotypes, and reveals methylation landscapes

The Long-Read Personalized OncoGenomics (POG) dataset comprises a cohort of 189 patient tumors and 41 matched normal samples sequenced using the Oxford Nanopore Technologies PromethION platform. This dataset from the POG program and the Marathon of Hope Cancer Centres Network includes DNA and RNA short-read sequence data, analytics, and clinical information. We show the potential of long-read sequencing for resolving complex cancer-related structural variants, viral integrations, and extrachromosomal circular DNA. Long-range phasing facilitates the discovery of allelically differentially methylated regions (aDMRs) and allele-specific expression, including recurrent aDMRs in the cancer genes RET and CDKN2A. Germline promoter methylation in MLH1 can be directly observed in Lynch syndrome. Promoter methylation in BRCA1 and RAD51C is a likely driver behind homologous recombination deficiency where no coding driver mutation was found. This dataset demonstrates applications for long-read sequencing in precision medicine and is available as a resource for developing analytical approaches using this technology.

Hematologic Cancer after Gene Therapy for Cerebral Adrenoleukodystrophy

BackgroundGene therapy with elivaldogene autotemcel (eli-cel) consisting of autologous CD34+ cells transduced with lentiviral vector containing ABCD1 complementary DNA (Lenti-D) has shown efficacy in clinical studies for the treatment of cerebral adrenoleukodystrophy. However, the risk of oncogenesis with eli-cel is unclear.MethodsWe performed integration-site analysis, genetic studies, flow cytometry, and morphologic studies in peripheral-blood and bone marrow samples from patients who received eli-cel therapy in two completed phase 2–3 studies (ALD-102 and ALD-104) and an ongoing follow-up study (LTF-304) involving the patients in both ALD-102 and ALD-104.ResultsHematologic cancer developed in 7 of 67 patients after the receipt of eli-cel (1 of 32 patients in the ALD-102 study and 6 of 35 patients in the ALD-104 study): myelodysplastic syndrome (MDS) with unilineage dysplasia in 2 patients at 14 and 26 months; MDS with excess blasts in 3 patients at 28, 42, and 92 months; MDS in 1 patient at 36 months; and acute myeloid leukemia (AML) in 1 patient at 57 months. In the 6 patients with available data, predominant clones contained lentiviral vector insertions at multiple loci, including at either MECOM–EVI1 (MDS and EVI1 complex protein EVI1 [ecotropic virus integration site 1], in 5 patients) or PRDM16 (positive regulatory domain zinc finger protein 16, in 1 patient). Several patients had cytopenias, and most had vector insertions in multiple genes within the same clone; 6 of the 7 patients also had somatic mutations (KRAS, NRAS, WT1, CDKN2A or CDKN2B, or RUNX1), and 1 of the 7 patients had monosomy 7. Of the 5 patients with MDS with excess blasts or MDS with unilineage dysplasia who underwent allogeneic hematopoietic stem-cell transplantation (HSCT), 4 patients remain free of MDS without recurrence of symptoms of cerebral adrenoleukodystrophy, and 1 patient died from presumed graft-versus-host disease 20 months after HSCT (49 months after receiving eli-cel). The patient with AML is alive and had full donor chimerism after HSCT; the patient with the most recent case of MDS is alive and awaiting HSCT.ConclusionsHematologic cancer developed in a subgroup of patients who were treated with eli-cel; the cases are associated with clonal vector insertions within oncogenes and clonal evolution with acquisition of somatic genetic defects. (Funded by Bluebird Bio; ALD-102, ALD-104, and LTF-304 ClinicalTrials.gov numbers, NCT01896102, NCT03852498, and NCT02698579, respectively.)

Regulation of R-Loops in DNA Tumor Viruses.

R-loops are triple-stranded nucleic acid structures that occur when newly synthesized single-stranded RNA anneals to duplex DNA upon the collision of replication forks with transcription complexes. These RNA-DNA hybrids facilitate several transcriptional processes in the cell and have been described extensively in the literature. Recently, evidence has emerged that R-loops are key regulators of DNA tumor virus transcription and the replication of their lifecycle. Studies have demonstrated that R-loops on the Human Papillomavirus (HPV) genome must be resolved to maintain genome maintenance and avoid viral integration, a hallmark of HPV cancers. For Epstein-Barr virus (EBV), R-loops are formed at the oriLyt to establish lytic replication. Structural maintenance of chromosome proteins 5/6 (SMC5/6) bind to these viral R-loops to repress EBV lytic replication. Most viruses in the herpesvirales order, such as KSHV, contain R-loop-forming sequences. In this perspective, we will describe the current, although limited, literature demonstrating the importance of RNA-DNA hybrids to regulate DNA virus transcription. We will also detail potential new areas of R-loop research and how these viruses can be used as tools to study the growing field of R-loops.

Deciphering the Molecular Landscape of Dengue Infection: Insights from gene expression profiling and Protein Interactions

Dengue fever (DF) is a viral infection recognized as one of the most rapidly spreading vector-borne diseases among humans. However, the molecular mechanisms underlying disease aetiology and potential therapeutic targets remain unclear. This study presents a thorough examination of differentially expressed genes (DEGs) throughout the spectrum of Dengue infection stages, offering insights into disease mechanisms and therapeutic targets. Through meticulous analysis of DEGs within each infection stage, key genes pertinent to disease progression are identified, highlighting their roles in host-virus interactions. Noteworthy discoveries include the upregulation of IFI27 and USP18 in mild infection, suggesting involvement in viral replication inhibition and host defence, alongside the downregulation of CMTM2, indicating alterations in immune-related functions. Similarly, in severe infection, upregulated genes like IGHV1-69 are linked to illness severity, while downregulated IL-13RA1 signifies disruptions in cytokine signaling. Overlapping DEGs between infection groups unveil shared biological processes, further elucidated through functional enrichment analysis, showcasing coordinated regulation of cellular processes and pathways. Integration of Dengue virus and human interaction network analysis reveals crucial insights into the mechanisms by which the virus mediates the disease progression and offers potential therapeutic opportunities for disease management.

Impact of membrane surface and module damage on virus removal and integrity in RO membranes

RO membrane modules are very effective in removing viruses and salts, but concerns remain regarding their long-term integrity in full-scale RO spiral wound systems. Membrane defects can arise from delamination, chlorine, or abrasive particle exposure, and module defects can arise from permeate tube, O-ring, and glue line damage. These issues compromise the membrane and module's performance, allowing viruses to pass that are not detected by conductivity monitoring. This paper assesses the impact of damage on virus removal using biological indicators (natural virus markers (NV)) and non-biological surrogates (salt, sulfate, rhodamine WT, pyranine). Three categories of module damage were studied and characterized using different autopsy techniques: membrane module component damage (permeate tube damage, O-ring damage, and membrane delamination), oxidative membrane damage (by hypochlorite exposure dose), and membrane surface damage (by abrasive particle exposure). Module component damage resulted in increased water permeability and decreased natural virus rejection. The conductivity remained similar to that of an intact module except in the case of permeate tube damage. Chlorine exposure (9000 ppm.h) didn't result in detectable NV markers in the permeate, indicating an intact support layer despite active layer damage. Abrasive particle exposure by suspended silicon carbide in the feed resulted in scratches, observed by SEM images, and a decline in the rejection of fluorescent marker, which indicates membrane surface damage. Results demonstrate that NV markers most consistently determine virus removal capacity in modules compromised by component damage. However, for assessing active layer damage, solutes like rhodamine-WT and pyranine prove more effective. This underscores the necessity of employing multiple indicators for a comprehensive evaluation of membrane integrity.

Metallophosphoesterase-Domain-Containing Protein 2 (MPPED2) Expression in High-Risk Human Papilloma Virus-Induced Cervical Carcinoma and Its Correlation With p16INK4A Protein.

Introduction Recently, the expression of metallophosphoesterase-domain-containing protein 2 (MPPED2) was identified in cervical cancer. However, its precise role and correlation with other tumor suppressor proteins, such as p16INK4A, is not well studied in high-risk human papillomavirus (HPV) integrated human cervical carcinoma. Hence, in the present study, we try to see the expression of MPPED2 in human cervical carcinoma and its correlation with age and p16INK4A protein expression level. Methods The prospective study consists of 200 samples of 150 known cervical carcinoma and 50 controls. Histopathological evaluation, immunohistochemical staining, and semi-quantitative scoring of the intensity of proteins were performed. Statistical analysis was performed with the Shapiro-Wilk test, Spearman's rho correlation sig. (two-tailed), and Student's t-test. Results The data show that among the 150 cases, 136 (68.0%) cervical carcinoma tissues express the presence of high-risk HPV viral genome integration in the host cell. The expression of p16INK4A protein is higher in those tissues identified with high-risk HPV viral genomes. In contrast, the expression of MPPED2 protein is lesser or absent in those cervical tissues that have the higher expression of p16INK4A protein and vice versa. There is a significant correlation (p=0.000) between age and p16INK4A protein expression but not with MPPED2. A significant linear correlation (p=0.000) is found between the p16INK4A and MPPED2 proteins. Conclusion It may support the therapeutic application of MPPED2 protein to prevent cervical carcinoma progression in the near future.

Exploring the tolerable region for HiBiT tag insertion in the hepatitis B virus genome.

Hepatitis B virus (HBV) is the principal causative agent of chronic hepatitis. Despite the availability of vaccines in many countries, HBV infection has spread worldwide and caused chronic infection. In chronic hepatitis B patients, liver inflammation leads to cirrhosis, and the accumulation of viral genome integration into host chromosomes leads to the development of hepatocellular carcinoma. The currently available treatment strategy cannot expect the eradication of HBV. To explore novel anti-HBV agents, a cell culture system that can detect HBV infection easily is indispensable. In this study, we examined the regions in the HBV genome where the high affinity and bright luminescence (HiBiT) tag could be inserted and established an HBV infection system to monitor infection by measuring the HiBiT signal by infecting the HiBiT-tagged HBV in sodium taurocholate cotransporting polypeptide-transduced HepG2 (HepG2/NTCP) cells. This system can contribute to screening for novel anti-HBV agents.

Versatile Cell Penetrating Peptide for Multimodal CRISPR Gene Editing in Primary Stem Cells.

CRISPR gene editing offers unprecedented genomic and transcriptomic control for precise regulation of cell function and phenotype. However, delivering the necessary CRISPR components to therapeutically relevant cell types without cytotoxicity or unexpected side effects remains challenging. Viral vectors risk genomic integration and immunogenicity while non-viral delivery systems are challenging to adapt to different CRISPR cargos, and many are highly cytotoxic. The arginine-alanine-leucine-alanine (RALA) cell penetrating peptide is an amphiphilic peptide that self-assembles into nanoparticles through electrostatic interactions with negatively charged molecules before delivering them across the cell membrane. This system has been used to deliver DNAs, RNAs, and small anionic molecules to primary cells with lower cytotoxicity compared to alternative non-viral approaches. Given the low cytotoxicity, versatility, and competitive transfection rates of RALA, we aimed to establish this peptide as a new CRISPR delivery system in a wide range of molecular formats across different editing modalities. We report that RALA was able to effectively encapsulate and deliver CRISPR in DNA, RNA, and ribonucleic protein (RNP) formats to primary mesenchymal stem cells (MSCs). Comparisons between RALA and commercially available reagents revealed superior cell viability leading to higher numbers of transfected cells and the maintenance of cell proliferative capacity. We then used the RALA peptide for the knock-in and knock-out of reporter genes into the MSC genome as well as for the transcriptional activation of therapeutically relevant genes. In summary, we establish RALA as a powerful tool for safer and effective delivery of CRISPR machinery in multiple cargo formats for a wide range of gene editing strategies.

Fibroblasts Regulate the Transformation Potential of Human Papillomavirus-positive Keratinocytes.

Persistent human papillomavirus (HPV) infection is necessary but insufficient for viral oncogenesis. Additional contributing co-factors, such as immune evasion and viral integration have been implicated in HPV-induced cancer progression. It is widely accepted that HPV+ keratinocytes require co-culture with fibroblasts to maintain viral episome expression, yet the exact mechanisms for this have yet to be elucidated. Here we present comprehensive RNA sequencing and proteomic analysis demonstrating that fibroblasts not only support the viral life cycle, but reduce HPV+ keratinocyte transformation. Our co-culture models offer novel insights into HPV-related transformation mechanisms.

The phenomenon of viral chromosomal integration

The literature review is devoted to the chromosomally integrating viruses, the integration property. These are revealed using modern diagnostic methods, including highthroughput sequencing. The review describes various types of viruses, such as retroviruses, adenoviruses, herpes viruses, papillomaviruses, hepatitis B, SARS-CoV-2 and others. These viruses have the ability to integrate their genomes into the host cell genomes and their prevalence. Modern information on the molecular mechanisms of viral integration and methods of differential diagnostics is presented. Each of these viruses has its own unique ways of interacting with the host cell genome to maintain a latent state, which determines the specifics of the infectious process and pathological consequences for the body due to the possibility of effective reactivation.

Endogenous viral elements are targeted by RNA silencing pathways in banana.

Endogenous banana streak virus (eBSV) integrants derived from three distinct species, present in Musa balbisiana (B) but not Musa acuminata (A) banana genomes are able to reconstitute functional episomal viruses causing banana streak disease in interspecific triploid AAB banana hybrids but not in the diploid (BB) parent line, which harbours identical eBSV loci. Here, we investigated the regulation of these eBSV. In-depth characterization of siRNAs, transcripts and methylation derived from eBSV using Illumina and bisulfite sequencing were carried out on eBSV-free Musa acuminata AAA plants and BB or AAB banana plants with eBSV. eBSV loci produce low-abundance transcripts covering most of the viral sequence and generate predominantly 24-nt siRNAs. siRNA accumulation is restricted to duplicated and inverted viral sequences present in eBSV. Both siRNA-accumulating and nonaccumulating sequences of eBSV in BB plants are heavily methylated in all three CG, CHG and CHH contexts. Our data suggest that eBSVs are controlled at the epigenetic level in BB diploids. This regulation not only prevents their awakening and systemic infection of the plant but is also probably involved in the inherent resistance of the BB plants to mealybug-transmitted viral infection. These findings are thus of relevance to other plant resources hosting integrated viruses.