ARTICLE | doi:10.20944/preprints202008.0548.v1
Subject: Life Sciences, Biophysics Keywords: promoter sequences; repetitive sequences; pausing; abortive initiation; RNA polymerase; dsDNA rigidity
Online: 25 August 2020 (11:28:21 CEST)
In the process of transcription initiation by RNA polymerase, promoter DNA sequences affect multiple reaction pathways determining the productivity of transcription. However, the question of how the molecular mechanism of transcription initiation depends on sequence properties of promoter DNA remains poorly understood. Here, combining the statistical mechanical approach with high-throughput sequencing results, we characterize abortive transcription and pausing during transcription initiation by Escherichia coli RNA polymerase at a genome-wide level. Our results suggest that initially transcribed sequences enriched with thymine bases represent the signal inducing abortive transcription. On the other hand, certain repetitive sequence elements broadly embedded in promoter regions constitute the signal inducing pausing. Both signals decrease the productivity of transcription initiation. Based on solution NMR and in vitro transcription measurements, we also suggest that repetitive sequence elements of promoter DNA modulate the rigidity of its double-stranded form, which profoundly influences the reaction coordinates of the productive initiation via pausing.
ARTICLE | doi:10.20944/preprints202206.0313.v1
Online: 22 June 2022 (10:02:33 CEST)
In the sugar industry, dextran generates difficulties in the manufacturing process. Crude dextranase (EC 184.108.40.206) to eliminate dextran in sugar is an effective practice. In this study, a synthetic dextranase encoding gene of the filamentous fungus Talaromyces minioluteus, lacking its putative native signal peptide (1-20 amino acids) and the next 30 amino acids (r-TmDEX49A-ΔSP-ΔN30), was fused to the Saccharomyces cerevisiae prepro -factor (MF-2) signal sequence and expressed in Komagataella phaffii under the constitutive GAP promoter. K. phaffii DEX49A-ΔSP-ΔN30, constitutively producing and secreting the truncated dextranase was obtained. The specific activity of the truncated variant resulted nearly the same in relation to the full-length mature enzyme (900-1000 U.mg-1 of protein). At shaker scale (100 mL) in YPG medium, the enzymatic activity was 273 U.mL-1. The highest production level was achieved in a fed-batch culture (30 h) at 5 L fermenter scale using the FM21-PTM1 culture medium. The enzymatic activity in the culture supernatant reached 1614 U.mL-1 and the productivity was 53800 U.L-1.h-1 (53.8 mg.L-1.h-1), the highest reported so far for a DEX49A variant. Dextran decreased r-TmDEX49A-ΔSP-ΔN30 mobility in affinity gel electrophoresis, providing evidence of carbohydrate-protein interactions. K. phaffii DEX49A-ΔSP-ΔN30 shows great potential as a methanol-free, commercial dextranase production system.
ARTICLE | doi:10.20944/preprints201810.0314.v1
Subject: Life Sciences, Other Keywords: hepatitis B virus (HBV); cccDNA; basal core promoter; X promoter; single nucleotide polymorphisms; logo analyses; genotype alignments
Online: 15 October 2018 (13:03:06 CEST)
Over 250 million people are infected chronically with hepatitis B virus (HBV), the leading cause of liver cancer worldwide. HBV persists due in part to its compact, stable minichromosome, the covalently-closed, circular DNA (cccDNA), which resides in the hepatocytes’ nuclei. Current therapies target downstream replication products, however, a true virological cure will require targeting the cccDNA. Finding targets on such a small, compact genome is challenging. For HBV, to remain replication-competent, it needs to maintain nucleotide fidelity in key regions, such as the promoter regions, to ensure that it can continue to utilize the necessary host proteins. HBVdb (HBV database) is a repository of HBV sequences spanning all genotypes (A-H) amplified from clinical samples, and hence implying an extensive collection of replication-competent viruses. Here, we analyzed the HBV sequences from HBVdb using bioinformatics tools to comprehensively assess the HBV core and X promoter regions amongst the nearly 70,000 HBV sequences for highly-conserved nucleotides and variant frequencies. Notably, there is a high degree of nucleotide conservation within specific segments of these promoter regions highlighting their importance in potential host protein-viral interactions and thus the virus’ viability. Such findings may have key implications for designing antivirals to target these areas.
REVIEW | doi:10.20944/preprints201807.0329.v1
Subject: Life Sciences, Biotechnology Keywords: bio-sensor; promoter; sensitivity; specificity; high-throughput screening (HTS); genetic promoter chip; “push and pull” mode; toxicity
Online: 18 July 2018 (10:22:39 CEST)
Promoter is a small region of DNA sequence in response to various transcription factors, which initiates a particular gene expression. The promoter-engineered bio-sensor can activate or repress gene expression through transcription factor recognizing specific molecules, such as polyamine, sugars, lactams, amino acids, organic acids or redox molecule, however, the reported applications of promoter enhanced bio-sensor are not too much. This review paper highlights the strategies of construction of promoter-gene engineered bio-sensor with human and bacteria’s genetic promoter array for high-throughput screening (HTS) molecular drugs, study of membrane protein’s localization and nucleocytoplasmic shuttling mechanism of regulating factor, enzyme activity, detection of the toxicity of intermediate chemicals, and probing bacteria density to improve value-added product titer. These bio-sensors’s sensitivity and specificity can be further improved by proposed approaches of Mn2+ and Mg2+ added random Error-prone PCR and site-directed mutagenesis which is applied for construction of bacteria’s “mutant library”. It is expected to establish flexible HTS platform (Bio-sensor array) to large-scale screen transcription factor-acting drugs, reducing the toxicity of intermediate compounds, and constructing gene dynamic regulatory system in “push and pull” mode to effectively regulate the valuable medicinal product production. This proposed novel promoter-engineered biosensors aided synthetic genetic circuit construction will maximize the efficiency of bio-synthesis of medicinal compound, which will greatly promote the development of microbial metabolic engineering and biomedical science.
ARTICLE | doi:10.20944/preprints202005.0495.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: Hedgehog pathway; Smoothened; Promoter; Methylation; Transcription factors
Online: 31 May 2020 (19:14:59 CEST)
Background: The hedgehog (HH) signaling pathway is a key regulator of embryonic patterning, tissue regeneration, stem cell renewal, and cancer growth. The smoothened (SMO) protein regulates the HH signaling pathway and has demonstrated oncogenic activity. Methods: To clarify the role of the HH signaling pathway in tumorigenesis, the expression profile of key HH signaling molecules, including SMO, PTCH1, GLI1, GLI2, and GLI3, were determined in thirty-three cancer cell lines. We performed a computational analysis of the upstream region of the SMO gene to identify the regulatory elements. Results: Three potential CpG islands and several putative SMO promoter elements were identified. Luciferase reporter assays mapped key SMO promoter elements, and functional binding sites for SP1, AP1, CREB, and AP-2a transcription factors in the core SMO promoter region were confirmed. A hypermethylated SMO promoter was identified in several cancer cell lines suggesting an important role for epigenetic silencing of SMO expression in certain cancer cells. Discussion: These results have important implications for our understanding of regulatory mechanisms controlling HH pathway activity and the molecular basis of SMO gene function. Moreover, this study may prove valuable for future research aimed at producing therapeutic downregulation of SMO expression in cancer cells.
ARTICLE | doi:10.20944/preprints202004.0264.v1
Subject: Life Sciences, Genetics Keywords: RBFOX3; HTERT; gastric cancer; promoter-binding protein; cancer biomarker
Online: 16 April 2020 (08:17:44 CEST)
Tumor invasion, metastasis, and recrudesce remain a considerable challenge in the treatment of gastric cancer (GC). Herein, we first identified that RBFOX3 (RNA binding protein fox-1 homolog 3) was significantly up-regulated in GC tissues and negatively linked to the survival rate of GC patients. RBFOX3 promoted cell division and cell cycle progression in vitro as well as in vivo. Furthermore, RBFOX3 increased cell invasion and migration ability. Interestingly, both the suppression of GC cell multiplication and invasion moderated by the silencing of RBFOX3 was rescued by HTERT up-regulation. Additionally, RBFOX3 augmented the resistance of GC cells to 5-fluorouracil (5-Fu) by repressing RBFOX3. Mechanistically, exogenous up-regulation of RBFOX3 triggered promoter activity and HTERT expression thereby enhancing the division and development of GC cells. Importantly, our findings revealed that RBFOX3 interacted with AP-2β to modulate the HTERT expression as demonstrated by co-immunoprecipitation analysis. In conclusion, our study indicates that high expression of RBFOX3 promotes GC progression and development but predicts worse prognosis by stimulating HTERT signaling. Moreover, the results suggest that the RBFOX3/AP-2β/HTERT pathway is a novel target for the development of therapeutic agents for the prevention and treatment of GC reappearance and metastasis.
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: Oral cancer; Oropharyngeal cancer; Tumor-suppressor genes; Promoter hypermethylation
Online: 19 March 2019 (12:56:24 CET)
Silencing of tumor suppressor genes (TSGs) by DNA promoter hypermethylation is an earlyevent in carcinogenesis; Hence TSGs may serve as early tumor biomarkers. We determinedthe promoter methylation levels of p16INK4a, RASSF1A, TIMP3 and PCQAP/MED15 TSGs in salivary DNA from oral cancer (OC), and oropharyngeal cancer (OPC) patients, using methylation specific PCR coupled with densitometry analysis. We assessed the association between DNA methylation of individual TSGs with OC and OPC risk factors. We evaluated the performance and the clinical validity of this quadruple methylation marker panel in discriminating OC and OPC patients from healthy controls using CombiROC web tool. Our study reported that RASSF1A, TIMP3 and PCQAP/MED15 TSGs were significantly hypermethylated in OC and OPC cases compared to healthy controls. We found that DNA methylation levels of TSGs were significantly augmented by smoking, alcohol use and betel quid chewing by indicating that the fact that frequent exposure to risk factors may drive oral and oropharyngeal carcinogenesis through TSG promoter hypermethylation. Also, this quadruple-methylation marker panel of p16INK4a, RASSF1A, TIMP3 and PCQAP/MED15 TSGs demonstrated excellent diagnostic accuracy in the early detection of OC at 91.7% sensitivity and 92.3% specificity, and OPC at 99.8% sensitivity and 92.1% specificity, from healthy controls.
REVIEW | doi:10.20944/preprints202110.0079.v1
Subject: Life Sciences, Biotechnology Keywords: genetic switch; yeast; synthetic transcription factor; synthetic promoter; directed evolution
Online: 5 October 2021 (11:19:46 CEST)
Genetic switches can be utilized for many purposes in synthetic biology including the assembly of complex genetic circuits to achieve sophisticated cellular systems and the construction of biosensors for real-time monitoring of intracellular metabolite concentrations. Although genetic switches have mainly been developed in prokaryotes to date, eukaryotic genetic switches are increasingly being reported as both rational and irrational engineering technologies mature. In this review, we describe genetic switches in yeast based on synthetic transcription factors and/or synthetic promoters. We also discuss directed evolution technologies for the rapid and robust construction of yeast genetic switches.
ARTICLE | doi:10.20944/preprints202102.0040.v1
Subject: Life Sciences, Biochemistry Keywords: APCDD1; HDAC5; germline variants; familial colorectal cancer; whole exome sequencing; promoter activity
Online: 1 February 2021 (14:04:24 CET)
Germline mutations in predisposition genes account for only 20% of all familial colorectal cancer (CRC) and the remaining genetic burden may be due to rare high-to-moderate-penetrance germline variants that are not explored. With the aim of identifying such potential cancer predisposing variants, we performed whole exome sequencing on three CRC cases and three unaffected members of a Polish family and identified two novel heterozygous variants; a coding variant in APC down-regulated 1 gene (APCDD1, p.R299H) and a non-coding variant in the 5’ untranslated region (UTR) of histone deacetylase 5 gene (HDAC5). Sanger sequencing confirmed the variants segregating with the disease and Taqman assays revealed 8 additional APCDD1 variants in a cohort of 1705 familial CRC patients and no further HDAC5 variants. Proliferation assays indicated an insignificant proliferative impact for the APCDD1 variant. Luciferase reporter assays using the HDAC5 variant resulted in an enhanced promoter activity. Targeting of transcription factor binding sites of SNAI-2 and TCF4 interrupted by HDAC5 variant showed a significant impact of TCF4 on promoter activity of mutated HDAC5. Our findings contribute not only to the identification of unrecognized genetic causes of familial CRC but also underline the importance of 5´UTR variants affecting transcriptional regulation and the pathogenesis of complex disorders.
Subject: Life Sciences, Biotechnology Keywords: pathway optimization; machine learning tools; enzyme activity prediction; promoter classification; expression tuning
Online: 26 August 2020 (04:05:47 CEST)
Successful engineering of a microbial host for efficient production of a target product from a given substrate can be viewed as an extensive optimization task. Such a task involves the selection of high activity enzymes as well as their gene expression regulatory control elements (i.e., promoters and ribosome binding sites). Finally, there is also the need to tune expression of multiple genes along a heterologous pathway to relieve constraints from rate-limiting step and help reduce metabolic burden on cells from unnecessary over-expression of high activity enzymes. While the aforementioned tasks could be performed through combinatorial experiments, such an approach incurs significant cost, time and effort, which is a handicap that can be relieved by application of modern machine learning tools. Such tools could attempt to predict high activity enzymes from sequence, but they are currently most usefully applied in classifying strong promoters from weaker ones as well as combinatorial tuning of expression of multiple genes. This perspective reviews the application of machine learning tools to aid metabolic pathway optimization through identifying challenges in metabolic engineering that could be overcome with the help of machine learning tools.
REVIEW | doi:10.20944/preprints201908.0176.v1
Subject: Biology, Other Keywords: G-quadruplex; dimer; tetramer; multimer; oligomer; telomere; promoter; R-loop; DNA:RNA hybrid
Online: 16 August 2019 (07:57:25 CEST)
G-quadruplexes are noncanonical nucleic acid structures formed from stacked guanine tetrads. They are frequently used as building blocks and functional elements in fields such as synthetic biology and also thought to play widespread biological roles. G-quadruplexes are often studied as monomers but can also form a variety of higher-order structures. This increases the structural and functional diversity of G-quadruplexes, and recent evidence suggests that it could also be biologically important. In this review we describe the types of multimeric topologies adopted by G-quadruplexes and highlight what is known about their sequence requirements. We also summarize the limited information available about potential biological roles of multimeric G-quadruplexes and suggest new approaches that could facilitate future studies of these structures.
Subject: Life Sciences, Biochemistry Keywords: dominant selectable marker; Aspergillus fumigatus; inducible marker; hph; ptrA; xylanase promoter; thiamine; hygromycin; pyrithiamine
Online: 24 May 2021 (13:22:44 CEST)
The hygromycin B phosphotransferase gene from Escherichia coli and the pyrithiamine resistance gene from Aspergillus oryzae are two dominant selectable marker genes widely used to genetically manipulate several fungal species. Despite the recent development of CRISPR/Cas9 and marker-free systems, in vitro molecular tools to study Aspergillus fumigatus, a saprophytic fungus causing life threatening diseases in immunocompromised hosts, still rely extensively on the use of dominant selectable markers. The limited number of drug selectable markers is already a critical aspect, but the possibility that their introduction into a microorganism could induce enhanced virulence or undesired effects on metabolic behavior, constitutes another problem. In this context, here we demonstrate that the use of ptrA in A. fumigatus leads to secretion of a compound that allows recovery of thiamine auxotrophy. In this study we developed a simple modification of the two commonly used dominant markers in which the development of resistance can be controlled by the xylose-inducible promoter PxylP from Penicillium chrysogenum. This strategy provides an easy solution to avoid undesired side effects since the marker expression can be readily silenced when not required.
ARTICLE | doi:10.20944/preprints202105.0247.v1
Subject: Biology, Anatomy & Morphology Keywords: IgLON; Lsamp; Ntm; Opcml; Negr1; alternative promoter; cell adhesion molecules; embryonic mouse brain; pallium
Online: 11 May 2021 (14:22:01 CEST)
The members of the IgLON superfamily of cell adhesion molecules facilitate fundamental cellular communication during brain development, maintain functional brain circuitry, and are associated with several neuropsychiatric disorders. Usage of alternative promoter-specific 1a and 1b mRNA isoforms in Lsamp, Opcml, Ntm and the single promoter of Negr1 in the mouse and human brain has been previously described. To determine the precise spatiotemporal expression dynamics of Lsamp, Opcml, Ntm isoforms and Negr1, in the developing brain, we generated isoform-specific RNA probes and carried out in situ hybridization in the developing (embryonic, E10.5, 13.5, 17; post natal, P0) and adult mouse brains. We show that promoter-specific expression of IgLONs is established early during pallial development (at E10.5), where it remains throughout its differentiation through adulthood. In the diencephalon, midbrain and hindbrain, strong expression patterns are initiated a few days later and begin fading after birth, being only faintly expressed during adulthood. Thus, the expression of specific IgLONs in the developing brain may provide the means for regionally specific functionality as well as for specific regional vulnerabilities. The current study will therefore improve the understanding of how IgLON genes are implicated in the development of neuropsychiatric disorders.
REVIEW | doi:10.20944/preprints202010.0482.v1
Subject: Life Sciences, Biochemistry Keywords: Inflammasome; NF-κB; IRF; NLRP3; caspase-1; epigenetic modification; transcription factor; chromatin; promoter; enhancer
Online: 23 October 2020 (10:41:25 CEST)
Inflammasomes are multimolecular complexes with potent inflammatory activity. As such, their activity is tightly regulated at the transcriptional and post-transcriptional levels. In this review, we present the transcriptional regulation of inflammasome genes from sensors (e.g NLRP3) to substrates (e.g. IL-1β). Lineage-determining transcription factors shape inflammasome responses in different cell types with profound consequences on the responsiveness to inflammasome-activating stimuli. Pro-inflammatory signals (sterile or microbial) have a key transcriptional impact on inflammasome genes, which is largely mediated by NF-κB and, that translates into higher antimicrobial immune responses. Furthermore, diverse intrinsic (e.g. circadian clock, metabolites) or extrinsic (e.g. xenobiotics) signals are integrated by signal-dependent transcription factors and chromatin structure changes to modulate transcriptionally inflammasome responses. Finally, anti-inflammatory signals (e.g. IL-10) counterbalance inflammasome genes induction to limit deleterious inflammation. Transcriptional regulations thus appear as the first line of inflammasome regulation to raise the defense level in front of stress and infections but also to limit excessive or chronic inflammation.
ARTICLE | doi:10.20944/preprints201911.0271.v1
Subject: Life Sciences, Genetics Keywords: breast cancer risk; GWAS; candidate causal variant; chromatin conformation capture; reporter gene activity; enhancer; promoter
Online: 24 November 2019 (05:12:07 CET)
Genome-wide association studies have revealed a locus at 8p12 that is associated with breast cancer risk. Fine-mapping of this locus identified 16 candidate causal variants (CCVs). However, as these variants are intergenic, their function is unclear. To map chromatin looping from this risk locus to a previously identified candidate target gene, DUSP4, we performed chromatin conformation capture analyses in normal and tumoral breast cell lines. We identified putative regulatory elements, containing CCVs, that loop to the DUSP4 promoter region. Using reporter gene assays, we found that the risk allele of CCV rs7461885 reduced the activity of a DUSP4 enhancer element, consistent with the function of DUSP4 as a tumor suppressor gene. Furthermore, the risk allele of CCV rs12155535, located in another DUSP4 enhancer element, was negatively correlated with looping of this element to the DUSP4 promoter region, suggesting that this allele would be associated with reduced expression. These findings provide the first evidence that CCV risk alleles downregulate DUSP4 expression, suggesting that this gene is a regulatory target of the 8p12 breast cancer risk locus.
ARTICLE | doi:10.20944/preprints202208.0042.v1
Subject: Medicine & Pharmacology, General Medical Research Keywords: HbA1c biomarker; type 2 diabetes; cancer risk profiling; serological diagnosis; oncoinformatic screening; genetic overexpression; promoter methylation
Online: 2 August 2022 (06:04:42 CEST)
This research aimed to figure out the applications of HbA1c protein and HbA1 gene as the prognostic biomarkers for assessing the risks of different cancers among male T2D patients in Bangladesh considering their serological and oncoinformatic parameters. Depending on the concentrations of HbA1c (%) of the T2D patients (n=300), their individual FBS (mmol/L); THABF (mmol/L); creatinine (mg/dl); SC (mg/dl); STGs (mg/dl); HDLC (mg/dl); and LDLC (mg/dl) were estimated. The values of the patients were compared with the control (n=60) group as the serological analysis. Besides, HbA1 gene (encoding hBA1c protein) overexpression and promotor methylation responsible for BLCA, BRCA, CHOL, COAD, LUAD, LUSC, PAAD, and PRAD cancers in the male T2D patients were profiled as the oncoinformatic parameters based on the sample types; caner stages; racial footprints; gender; age; nodal metastasis; p53 methylations; pancreatitis; diabetes status; smoking behaviors; and overall/disease-free survivability. Finally, the ‘HbA1 gene strings’ responsible for genetic coexpression; endophytic vesicle regulation; antioxidant regulation; oxygen species metabolic regulation; and gene-mediated response to the reactive oxygen molecules were studied comprehensively. A strong correlation between BMI and FBS was observed in both the patients and the control (P<0.0001). Similarly, the values of FBS, THABF, and creatinine resulted in equal significance (P<0.0001) as compared to the HbA1c concentrations of all the T2D and control individuals. The SC, STGs, HDLC, and LDLC concentrations regulated ardently in both the control (P<0.0001), and patients group (P<0.0001), while HbA1c ranged from 3.8-5.8%, and 5.11-15.8% respectively. HbA1 gene is found downregulating with cancer progressed in most of the oncoinformatic parameters. According to the DA, CS, EI, CE, PC, NC, GF, H, and AT profiles; the HbA1 gene interacts with 8 other genes responsible for creating a protein cluster comprising- AHSP, HBA1, HBA2, HBB, HBD, HBE1, HBG2, RPS12, and RPS19 proteins for cancer formation. To recapitulate, HbA1c protein and HbA1 gene can be used as the prognostic serological and molecular biomarkers respectively for determining the risks of cancers among male chronic T2D patients.
ARTICLE | doi:10.20944/preprints202011.0400.v1
Subject: Biology, Anatomy & Morphology Keywords: Geminivirus; bipartite begomovirus; transcriptional trans-activation; abscisic acid; promoter motifs; AC2; BV1; mungbean yellow mosaic virus
Online: 16 November 2020 (08:44:26 CET)
Geminiviruses possess single-stranded, circular DNA genomes, and control the transcription of their late genes, including BV1 of many bipartite begomoviruses, through transcriptional activation by the early expressing AC2 protein. DNA binding by AC2 is not sequence-specific, hence the specificity of AC2 activation is thought to be conferred by plant transcription factors (TFs) recruited by AC2 in infected cells. However, the exact TFs AC2 recruits are not known for most viruses. Here we report a systematic examination of the BV1 promoter (PBV1) of mungbean yellow mosaic virus (MYMV) for conserved promoter motifs. We found that MYMV PBV1 contains three abscisic acid (ABA)-responsive elements (ABREs) within its first 70 nucleotides. Deleting these ABREs, or mutating them all via site-directed mutagenesis, abolished the capacity of PBV1 to respond to AC2-mediated transcriptional activation. Furthermore, ABRE and other related ABA-responsive elements were prevalent in more than a dozen Old World begomoviruses we inspected. Together these findings suggest that ABA-responsive TFs may be recruited by AC2 to BV1 promoters of these viruses to confer specificity to AC2 activation. These observations are expected to guide the search for the actual TF(s), furthering our understanding of the mechanism of AC2 action.
ARTICLE | doi:10.20944/preprints201701.0105.v1
Subject: Life Sciences, Biotechnology Keywords: magnetic hyperthermia; gene therapies; heat shock protein promoter; in vivo optical imaging; magnetic polymer-coated nanoparticles
Online: 24 January 2017 (04:14:19 CET)
The present work aims to demonstrate that colloidal dispersions of magnetic iron oxide nanoparticles stabilized with dextran macromolecules placed in an alternating magnetic field can not only produce heat, but also that these particles could be used in vivo for local and non-invasive deposition of a thermal dose sufficient to trigger thermo-induced gene expression. Iron oxide nanoparticles were first characterized in vitro on a bio-inspired setup, and then they were assayed in vivo using a transgenic mouse strain expressing the luciferase reporter gene under transcriptional control of a thermosensitive promoter. Iron oxide nanoparticles dispersions were applied topically on the mouse skin or injected sub-cutaneously with Matrigel™ to generate so called pseudo tumors. Temperature was monitored continuously with a feedback loop to control the power of the magnetic field generator and to avoid overheating. Thermo-induced luciferase expression was followed by bioluminescence imaging 6 hours after heating. We showed that dextran-coated magnetic iron oxide nanoparticles dispersions were able to induce in vivo mild hyperthermia compatible with thermo-induced gene expression in surrounding tissues and without impairing cell viability. These data open new therapeutic perspectives for using mild magnetic hyperthermia as non-invasive modulation of tumor microenvironment by local thermo-induced gene expression or drug release.
REVIEW | doi:10.20944/preprints202209.0482.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: Telomerase reverse transcriptase; TERT; TERT promoter; TERTp; human papillomavirus; HPV; Epstein Barr virus (EBV); Kaposi sarcoma-associated herpesvirus; HHV-8; hepatitis B virus; HBV; hepatitis C virus; HCV; human T-cell leukemia virus-1; HTLV-1
Online: 30 September 2022 (10:11:58 CEST)
Human oncoviruses are able to subvert telomerase function in cancer cells through multiple strategies. The activity of the catalytic subunit of telomerase (TERT) is commonly enhanced in virus-related cancers. Viral oncoproteins, such as high-risk human papillomavirus (HPV) E6, Epstein-Barr virus (EBV) LMP1, Kaposi sarcoma-associated herpesvirus (HHV-8) LANA, hepatitis B virus (HBV) HBVx, hepatitis C virus (HCV) core protein and human T-cell leukemia virus-1 (HTLV-1) tax protein, interact with regulatory elements in the infected cells and contribute to the transcriptional activation of TERT gene. Specifically, viral oncoproteins have been shown to bind TERT promoter, to induce post-transcriptional alterations of TERT mRNA and to cause epigenetic modifications, which have important effects on the regulation of telomeric and extra-telomeric functions of the telomerase. Other viruses, such as herpesviruses, operate by integrating their genomes within the telomeres or by inducing alternative lengthening of telomeres (ALT) in non-ALT cells. In this review, we recapitulate recent findings on virus-telomerase/telomeres interplay and the importance of TERT-related oncogenic pathways activated by cancer causing viruses.