scholarly journals Characterization of Endogenous Retroviruses in Sheep

2003 ◽  
Vol 77 (20) ◽  
pp. 11268-11273 ◽  
Author(s):  
Nikolai Klymiuk ◽  
Mathias Müller ◽  
Gottfried Brem ◽  
Bernhard Aigner
Keyword(s):  
Endogenous Retrovirus ◽  
Ovis Aries ◽  
Endogenous Retroviruses ◽  
Open Reading Frames ◽  
In Vivo Experiments ◽  
Pregnant Sheep ◽  
Reading Frames

ABSTRACT Endogenous retrovirus (ERV) sequences have been found in all mammals. In vitro and in vivo experiments revealed ERV activation and cross-species infection in several species. Sheep (Ovis aries) are used for various biotechnological purposes; however, they have not yet been comprehensively screened for ERV sequences. Therefore, the aim of the study was to classify the ERV sequences in the ovine genome (OERV) by analyzing the retroviral pro-pol sequences. Three OERV β families and nine OERV γ families were revealed. Novel open reading frames (ORF) in the amplified proviral fragment were found in one OERV β family and two OERV γ families. Hybrid OERV produced by putative recombination events were not detected. Quantitative analysis of the OERV sequences in the ovine genome revealed no relevant variations in the endogenous retroviral loads of different breeds. Expression analysis of different tissues from fetal and pregnant sheep detected mRNA from both gammaretrovirus families, showing ORF fragments. Thus, the release of retroviruses from sheep cells cannot be excluded.

scholarly journals Ancient Adversary – HERV-K (HML-2) in Cancer

2021 ◽  
Vol 11 ◽  
Author(s):  
Eoin Dervan ◽  
Dibyangana D. Bhattacharyya ◽  
Jake D. McAuliffe ◽  
Faizan H. Khan ◽  
Sharon A. Glynn
Keyword(s):  
Tumour Progression ◽  
Endogenous Retroviruses ◽  
Open Reading Frames ◽  
Human Endogenous Retroviruses ◽  
Viral Particles ◽  
Metastatic Capacity ◽  
Coding Capacity ◽  
Reading Frames

Human endogenous retroviruses (HERV), ancient integrations of exogenous viruses, make up 8% of our genome. Long thought of as mere vestigial genetic elements, evidence is now accumulating to suggest a potential functional role in numerous pathologies including neurodegenerative diseases, autoimmune disorders, and multiple cancers. The youngest member of this group of transposable elements is HERV-K (HML-2). Like the majority of HERV sequences, significant post-insertional mutations have disarmed HERV-K (HML-2), preventing it from producing infectious viral particles. However, some insertions have retained limited coding capacity, and complete open reading frames for all its constituent proteins can be found throughout the genome. For this reason HERV-K (HML-2) has garnered more attention than its peers. The tight epigenetic control thought to suppress expression in healthy tissue is lost during carcinogenesis. Upregulation of HERV-K (HML-2) derived mRNA and protein has been reported in a variety of solid and liquid tumour types, and while causality has yet to be established, progressively more data are emerging to suggest this phenomenon may contribute to tumour growth and metastatic capacity. Herein we discuss its potential utility as a diagnostic tool and therapeutic target in light of the current in vitro, in vivo and clinical evidence linking HERV-K (HML-2) to tumour progression.

scholarly journals Structural basis for Fullerene geometry in a human endogenous retrovirus capsid

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Oliver Acton ◽  
Tim Grant ◽  
Giuseppe Nicastro ◽  
Neil J. Ball ◽  
David C. Goldstone ◽  
...  
Keyword(s):  
Early Stage ◽  
Endogenous Retrovirus ◽  
Endogenous Retroviruses ◽  
Open Reading Frames ◽  
Structural Basis ◽  
Human Endogenous Retrovirus ◽  
Structural Protein ◽  
Human Endogenous Retroviruses ◽  
Reading Frames

AbstractThe HML2 (HERV-K) group constitutes the most recently acquired family of human endogenous retroviruses, with many proviruses less than one million years old. Many maintain intact open reading frames and provirus expression together with HML2 particle formation are observed in early stage human embryo development and are associated with pluripotency as well as inflammatory disease, cancers and HIV-1 infection. Here, we reconstruct the core structural protein (CA) of an HML2 retrovirus, assemble particles in vitro and employ single particle cryogenic electron microscopy (cryo-EM) to determine structures of four classes of CA Fullerene shell assemblies. These icosahedral and capsular assemblies reveal at high-resolution the molecular interactions that allow CA to form both pentamers and hexamers and show how invariant pentamers and structurally plastic hexamers associate to form the unique polyhedral structures found in retroviral cores.

scholarly journals Analysis of Early Promoters of theBacillus Bacteriophage GA-1

2001 ◽  
Vol 183 (23) ◽  
pp. 6965-6970 ◽  
Author(s):  
José A. Horcajadas ◽  
Wilfried J. J. Meijer ◽  
Fernando Rojo ◽  
Margarita Salas
Keyword(s):  
Bacillus Subtilis ◽  
In Vitro Transcription ◽  
Open Reading Frames ◽  
Early Infection ◽  
Infection Cycle ◽  
Reading Frames

ABSTRACT Bacteriophage GA-1, which infects Bacillus sp. strain G1R, is evolutionarily related to phage φ29, which infectsBacillus subtilis. We report the characterization of several GA-1 promoters located at either end of its linear genome. Some of them are unique for GA-1 and drive the expression of open reading frames that have no counterparts in the genome of φ29 or related phages. These unique promoters are active at early infection times and are repressed at late times. In vitro transcription reactions revealed that the purified GA-1-encoded protein p6 represses the activity of these promoters, although the amount of p6 required to repress transcription was different for each promoter. The level of protein p6 produced in vivo increases rapidly during the first stage of the infection cycle. The protein p6 concentration may serve to modulate the expression of these early promoters as infection proceeds.

scholarly journals Characterization of the Pasteurella multocida hgbA Gene Encoding a Hemoglobin-Binding Protein

2002 ◽  
Vol 70 (11) ◽  
pp. 5955-5964 ◽  
Author(s):  
Montserrat Bosch ◽  
M. Elena Garrido ◽  
Montserrat Llagostera ◽  
Ana M. Pérez de Rozas ◽  
Ignacio Badiola ◽  
...  
Keyword(s):  
Pasteurella Multocida ◽  
Bacterial Pathogen ◽  
Open Reading Frames ◽  
Transcriptional Unit ◽  
Gene Encoding ◽  
Hemoglobin Binding ◽  
Reading Frames

ABSTRACT Reverse transcriptase PCR analyses have demonstrated that open reading frames (ORFs) PM0298, PM0299, and PM0300 of the animal pathogen Pasteurella multocida constitute a single transcriptional unit. By cloning and overexpression studies in Escherichia coli cells, the product of ORF PM0300 was shown to bind hemoglobin in vitro; this ORF was therefore designated hgbA. In vitro and in vivo quantitative assays demonstrated that the P. multocida hgbA mutant bound hemoglobin to the same extent as the wild-type strain, although the adsorption kinetics was slightly slower for the hgbA cells. In agreement with this, the virulence of P. multocida hgbA cells was not affected, suggesting that other functional hemoglobin receptor proteins must be present in this organism. On the other hand, P. multocida mutants defective in PM0298 and PM0299 could be isolated only when a plasmid containing an intact copy of the gene was present in the cells, suggesting that these genes are essential for the viability of this bacterial pathogen. By adapting the recombinase-based expression technology in vivo to P. multocida, we also demonstrated that the transcriptional PM0298-PM0299-hgbA unit is iron regulated and that its expression is triggered in the first 2 h following infection in a mouse model. Furthermore, hybridization experiments showed that the hgbA gene is widespread in P. multocida strains regardless of their serotype or the animal from which they were isolated.

MOLECULAR CHARACTERIZATION OF A NOVEL RAT PARVOVIRUS IN TAIWAN

2014 ◽  
Vol 40 (01) ◽  
pp. 11-19 ◽  
Author(s):  
Yi-Chun Liao ◽  
Ming-Hseng Wang ◽  
Cho-Hua Wan
Keyword(s):  
Molecular Characterization ◽  
Open Reading Frames ◽  
Infectious Agents ◽  
Sequence Comparisons ◽  
Laboratory Rats ◽  
Laboratory Rodents ◽  
Reading Frames

Rodent parvoviruses are among the most prevalent infectious agents in laboratory rodents and have been shown to interfere with in vivo and in vitro research. A newly recognized rat parvovirus (RPV) that is distinct from the prototypic RPV was recently identified in naturally infected laboratory rats in Taiwan. Nucleotide and amino acid sequence comparisons showed that this newly identified variant of RPV is most closely related to rat parvovirus type 1a (RPV-1a) and type 1b (RPV-1b) and is distinctly different from type UT (RPV/UT) and other rodent parvoviruses. This variant was designated rat parvovirus type National Taiwan University 1 (RPV-NTU1). Phylogenetic and sequence analyses revealed that RPV-NTU1 contains conserved open reading frames with an overall genome organization similar to known RPV-1. RPV-NTU1 is the second RPV-1 variant whose full-length molecular characterization has been performed.

scholarly journals Enlisting the Ixodes scapularis Embryonic ISE6 Cell Line to Investigate the Neuronal Basis of Tick—Pathogen Interactions

Pathogens ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 70
Author(s):  
Lourdes Mateos-Hernández ◽  
Natália Pipová ◽  
Eléonore Allain ◽  
Céline Henry ◽  
Clotilde Rouxel ◽  
...  
Keyword(s):  
Cell Line ◽  
Peripheral Nerves ◽  
Ixodes Scapularis ◽  
Embryonic Cell ◽  
Cell Subpopulation ◽  
In Vivo Experiments

Neuropeptides are small signaling molecules expressed in the tick central nervous system, i.e., the synganglion. The neuronal-like Ixodes scapularis embryonic cell line, ISE6, is an effective tool frequently used for examining tick–pathogen interactions. We detected 37 neuropeptide transcripts in the I. scapularis ISE6 cell line using in silico methods, and six of these neuropeptide genes were used for experimental validation. Among these six neuropeptide genes, the tachykinin-related peptide (TRP) of ISE6 cells varied in transcript expression depending on the infection strain of the tick-borne pathogen, Anaplasma phagocytophilum. The immunocytochemistry of TRP revealed cytoplasmic expression in a prominent ISE6 cell subpopulation. The presence of TRP was also confirmed in A. phagocytophilum-infected ISE6 cells. The in situ hybridization and immunohistochemistry of TRP of I. scapularis synganglion revealed expression in distinct neuronal cells. In addition, TRP immunoreaction was detected in axons exiting the synganglion via peripheral nerves as well as in hemal nerve-associated lateral segmental organs. The characterization of a complete Ixodes neuropeptidome in ISE6 cells may serve as an effective in vitro tool to study how tick-borne pathogens interact with synganglion components that are vital to tick physiology. Therefore, our current study is a potential stepping stone for in vivo experiments to further examine the neuronal basis of tick–pathogen interactions.

scholarly journals Genomic Sequence of Rhesus Cytomegalovirus 180.92: Insights into the Coding Potential of Rhesus Cytomegalovirus

2006 ◽  
Vol 80 (8) ◽  
pp. 4179-4182 ◽  
Author(s):  
Pierre Rivailler ◽  
Amitinder Kaur ◽  
R. Paul Johnson ◽  
Fred Wang
Keyword(s):  
Genomic Sequence ◽  
Open Reading Frames ◽  
Rhesus Cytomegalovirus ◽  
Human Cmv ◽  
Coding Capacity ◽  
Coding Potential ◽  
Reading Frames ◽  
Genetic Rearrangements

ABSTRACT A pathogenic isolate of rhesus cytomegalovirus (rhCMV 180.92) was cloned, sequenced, and annotated. Comparisons with the published rhCMV 68.1 genome revealed 8 open reading frames (ORFs) in isolate 180.92 that are absent in 68.1, 10 ORFs in 68.1 that are absent in 180.92, and 34 additional ORFs that were not previously annotated. Most of the differences appear to be due to genetic rearrangements in both isolates from a region that is frequently altered in human CMV (hCMV) during in vitro passage. These results indicate that the rhCMV ORF repertoire is larger than previously recognized. Like hCMV, understanding of the complete coding capacity of rhCMV is complicated by genomic instability and may require comparisons with additional isolates in vitro and in vivo.

scholarly journals Evaluation of Radiolabeled Girentuximab In Vitro and In Vivo

2018 ◽  
Vol 11 (4) ◽  
pp. 132 ◽  
Author(s):  
Tais Basaco ◽  
Stefanie Pektor ◽  
Josue Bermudez ◽  
Niurka Meneses ◽  
Manfred Heller ◽  
...  
Keyword(s):  
Specific Binding ◽  
Sodium Ascorbate ◽  
Tumor Uptake ◽  
Tetraacetic Acid ◽  
In Vivo Experiments ◽  
Caix Expression ◽  
Tetraazacyclododecane Tetraacetic Acid

Girentuximab (cG250) targets carbonic anhydrase IX (CAIX), a protein which is expressed on the surface of most renal cancer cells (RCCs). cG250 labeled with 177Lu has been used in clinical trials for radioimmunotherapy (RIT) of RCCs. In this work, an extensive characterization of the immunoconjugates allowed optimization of the labeling conditions with 177Lu while maintaining immunoreactivity of cG250, which was then investigated in in vitro and in vivo experiments. cG250 was conjugated with S-2-(4-isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane tetraacetic acid (DOTA(SCN)) by using incubation times between 30 and 90 min and characterized by mass spectrometry. Immunoconjugates with five to ten DOTA(SCN) molecules per cG250 molecule were obtained. Conjugates with ratios less than six DOTA(SCN)/cG250 had higher in vitro antigen affinity, both pre- and postlabeling with 177Lu. Radiochemical stability increased, in the presence of sodium ascorbate, which prevents radiolysis. The immunoreactivity of the radiolabeled cG250 tested by specific binding to SK-RC-52 cells decreased when the DOTA content per conjugate increased. The in vivo tumor uptake was < 10% ID/g and independent of the total amount of protein in the range between 5 and 100 µg cG250 per animal. Low tumor uptake was found to be due to significant necrotic areas and heterogeneous CAIX expression. In addition, low vascularity indicated relatively poor accessibility of the CAIX target.

E1−E4+ Adenoviral Gene Transfer Vectors Function as a “Pro-Life” Signal to Promote Survival of Primary Human Endothelial Cells

Blood ◽  
1999 ◽  
Vol 93 (9) ◽  
pp. 2936-2944 ◽  
Author(s):  
Ramachandran Ramalingam ◽  
Shahin Rafii ◽  
Stefan Worgall ◽  
Douglas E. Brough ◽  
Ronald G. Crystal
Keyword(s):  
Endothelial Cells ◽  
Open Reading Frames ◽  
Adenoviral Gene Transfer ◽  
Vector Genome ◽  
Transfer Vectors ◽  
Reading Frames ◽  
Human Endothelium ◽  
Pro Life

Abstract Although endothelial cells are quiescent and long-lived in vivo, when they are removed from blood vessels and cultured in vitro they die within days to weeks. In studies of the interaction of E1−E4+ replication–deficient adenovirus (Ad) vectors and human endothelium, the cells remained quiescent and were viable for prolonged periods. Evaluation of these cultures showed that E1−E4+ Ad vectors provide an “antiapoptotic” signal that, in association with an increase in the ratio of Bcl2 to Bax levels, induces the endothelial cells to enter a state of “suspended animation,” remaining viable for at least 30 days, even in the absence of serum and growth factors. Although the mechanisms initiating these events are unclear, the antiapoptoic signal requires the presence of E4 genes in the vector genome, suggesting that one or more E4 open reading frames of subgroup C Ad initiate a “pro-life” program that modifies cultured endothelial cells to survive for prolonged periods.

scholarly journals Human APOBEC3G Prevents Emergence of Infectious Endogenous Retrovirus in Mice

2019 ◽  
Vol 93 (20) ◽  
Author(s):  
Rebecca S. Treger ◽  
Maria Tokuyama ◽  
Huiping Dong ◽  
Karen Salas-Briceno ◽  
Susan R. Ross ◽  
...  
Keyword(s):  
Ectopic Expression ◽  
Endogenous Retrovirus ◽  
Endogenous Retroviruses ◽  
Toll Like Receptor ◽  
Restriction Factors ◽  
Cytidine Deaminases ◽  
Endogenous Loci ◽  
Human Apobec3g

ABSTRACT Endogenous retroviruses (ERV) are found throughout vertebrate genomes, and failure to silence their activation can have deleterious consequences on the host. Mutation and subsequent disruption of ERV loci is therefore an indispensable component of the cell-intrinsic defenses that maintain the integrity of the host genome. Abundant in vitro and in silico evidence have revealed that APOBEC3 cytidine-deaminases, including human APOBEC3G (hA3G), can potently restrict retrotransposition; yet, in vivo data demonstrating such activity is lacking, since no replication-competent human ERV have been identified. In mice deficient for Toll-like receptor 7 (TLR7), transcribed ERV loci can recombine and generate infectious ERV. In this study, we show that ectopic expression of hA3G can prevent the emergence of replication-competent, infectious ERV in Tlr7−/− mice. Mice encode one copy of Apobec3 in their genome. ERV reactivation in Tlr7−/− mice was comparable in the presence or absence of Apobec3. In contrast, expression of a human APOBEC3G transgene abrogated emergence of infectious ERV in the Tlr7−/− background. No ERV RNA was detected in the plasma of hA3G+ Apobec3−/− Tlr7−/− mice, and infectious ERV virions could not be amplified through coculture with permissive cells. These data reveal that hA3G can potently restrict active ERV in vivo and suggest that expansion of the APOBEC3 locus in primates may have helped to provide for the continued restraint of ERV in the human genome. IMPORTANCE Although APOBEC3 proteins are known to be important antiviral restriction factors in both mice and humans, their roles in the restriction of endogenous retroviruses (ERV) have been limited to in vitro studies. Here, we report that human APOBEC3G expressed as a transgene in mice prevents the emergence of infectious ERV from endogenous loci. This study reveals that APOBEC3G can powerfully restrict active retrotransposons in vivo and demonstrates how transgenic mice can be used to investigate host mechanisms that inhibit retrotransposons and reinforce genomic integrity.

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