314 results match your criteria transposon lentivirus


Saccharomyces cerevisiae RNA lariat debranching enzyme, Dbr1p, is required for completion of reverse transcription by the retrovirus-like element Ty1 and cleaves branched Ty1 RNAs.

Authors:
Thomas M Menees

Mol Genet Genomics 2021 Mar 19;296(2):409-422. Epub 2021 Jan 19.

School of Biological and Chemical Sciences, University of Missouri-Kansas City, Kansas City, MO, USA.

RNA debranching enzymes are 2'-5' phosphodiesterases found in all eukaryotes. Their main role is cleavage of intron RNA lariat branch points, promoting RNA turnover via exonucleases. Consistent with this role, cells with reduced RNA debranching enzyme activity accumulate intron RNA lariats. Read More

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Structural Mimicry Drives HIV-1 Rev-Mediated HERV-K Expression.

J Mol Biol 2020 12 14;432(24):166711. Epub 2020 Nov 14.

Protein-Nucleic Acid Interaction Section, Structural Biophysics Laboratory, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA.

Expression of the Human Endogenous Retrovirus Type K (HERV-K), the youngest and most active HERV, has been associated with various cancers and neurodegenerative diseases. As in all retroviruses, a fraction of HERV-K transcripts is exported from the nucleus in unspliced or incompletely spliced forms to serve as templates for translation of viral proteins. In a fraction of HERV-K loci (Type 2 proviruses), nuclear export of the unspliced HERV-K mRNA appears to be mediated by a cis-acting signal on the mRNA, the RcRE, and the protein Rec-these are analogous to the RRE-Rev system in HIV-1. Read More

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December 2020

HIV-1 infection activates endogenous retroviral promoters regulating antiviral gene expression.

Nucleic Acids Res 2020 11;48(19):10890-10908

Institute of Molecular Virology, Ulm University Medical Center, Ulm 89081, Germany.

Although endogenous retroviruses (ERVs) are known to harbor cis-regulatory elements, their role in modulating cellular immune responses remains poorly understood. Using an RNA-seq approach, we show that several members of the ERV9 lineage, particularly LTR12C elements, are activated upon HIV-1 infection of primary CD4+ T cells. Intriguingly, HIV-1-induced ERVs harboring transcription start sites are primarily found in the vicinity of immunity genes. Read More

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November 2020

Endogenous Retroviruses Walk a Fine Line between Priming and Silencing.

Viruses 2020 07 23;12(8). Epub 2020 Jul 23.

Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.

Endogenous retroviruses (ERVs) in mammals are closely related to infectious retroviruses and utilize host tRNAs as a primer for reverse transcription and replication, a hallmark of long terminal repeat (LTR) retroelements. Their dependency on tRNA makes these elements vulnerable to targeting by small RNAs derived from the 3'-end of mature tRNAs (3'-tRFs), which are highly expressed during epigenetic reprogramming and potentially protect many tissues in eukaryotes. Here, we review some key functions of ERV reprogramming during mouse and human development and discuss how small RNA-mediated silencing maintains genome stability when ERVs are temporarily released from heterochromatin repression. Read More

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Comprehensive Analysis of HERV Transcriptome in HIV+ Cells: Absence of HML2 Activation and General Downregulation of Individual HERV Loci.

Viruses 2020 04 23;12(4). Epub 2020 Apr 23.

Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato-SS554, 09042 Monserrato, Cagliari, Italy.

Human endogenous retrovirus (HERV) expression is currently studied for its possible activation by HIV infection. In this context, the HERV-K(HML2) group is the most investigated: it has been proposed that HIV-1 infection can prompt HML2 transcription, and that HML2 proteins can affect HIV-1 replication, either complementing HIV or possibly influencing antiretroviral therapy. However, little information is available on the expression of other HERV groups in HIV infection. Read More

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Retrotransposition and senescence in mouse heart tissue by viral protein R of human immunodeficiency virus-1.

Exp Mol Pathol 2020 06 31;114:104433. Epub 2020 Mar 31.

Department of Intractable Diseases, Research Institute, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku, Tokyo 162-8655, Japan. Electronic address:

Combination antiretroviral therapy (cART) has greatly improved the prognosis of patients with human immunodeficiency virus type-1 (HIV-1) infection. However, cardiovascular disease (CVD) remains a serious issue even in the post-cART era. Viral protein R (Vpr), an accessory gene product of HIV-1, exerts pleiotropic activities such as the induction of DNA damage signals, apoptosis by mitochondrial membrane depolarization, G2/M-phase cell cycle abnormalities, and retrotransposition. Read More

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Endogenous Retroviral Envelope Syncytin Induces HIV-1 Spreading and Establishes HIV Reservoirs in Placenta.

Cell Rep 2020 03;30(13):4528-4539.e4

Department of Medical Microbiology and Immunology, University of California, Davis, Davis, CA 95616, USA; Department of Internal Medicine, Meharry Medical College, Nashville, TN 37208, USA. Electronic address:

Radical cure of HIV-1 (HIV) is hampered by the establishment of HIV reservoirs and persistent infection in deep tissues despite suppressive antiretroviral therapy (ART). Here, we show that among HIV-positive women receiving suppressive ART, cells from placental tissues including trophoblasts contain HIV RNA and DNA. These viruses can be reactivated by latency reversal agents. Read More

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Deamination hotspots among APOBEC3 family members are defined by both target site sequence context and ssDNA secondary structure.

Nucleic Acids Res 2020 02;48(3):1353-1371

Veterinary Medicine Graduate Program, University of Minnesota, Minneapolis, MN 55455 USA.

The human apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like 3 (APOBEC3, A3) family member proteins can deaminate cytosines in single-strand (ss) DNA, which restricts human immunodeficiency virus type 1 (HIV-1), retrotransposons, and other viruses such as hepatitis B virus, but can cause a mutator phenotype in many cancers. While structural information exists for several A3 proteins, the precise details regarding deamination target selection are not fully understood. Here, we report the first parallel, comparative analysis of site selection of A3 deamination using six of the seven purified A3 member enzymes, oligonucleotides having 5'TC3' or 5'CT3' dinucleotide target sites, and different flanking bases within diverse DNA secondary structures. Read More

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February 2020

Genetic Modification of Brain Organoids.

Front Cell Neurosci 2019 17;13:558. Epub 2019 Dec 17.

Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.

Brain organoids have become increasingly used systems allowing 3D-modeling of human brain development, evolution, and disease. To be able to make full use of these modeling systems, researchers have developed a growing toolkit of genetic modification techniques. These techniques can be applied to mature brain organoids or to the preceding embryoid bodies (EBs) and founding cells. Read More

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December 2019

HIV-1 Rev interacts with HERV-K RcREs present in the human genome and promotes export of unspliced HERV-K proviral RNA.

Retrovirology 2019 12 16;16(1):40. Epub 2019 Dec 16.

Myles H. Thaler Center for AIDS and Human Retrovirus Research and the Department of Microbiology, Immunology, Cancer Biology, University of Virginia, Charlottesville, 22908, USA.

Background: The HERV-K (HML-2) viruses are the youngest of the human endogenous retroviruses. They are present as several almost complete proviral copies and numerous fragments in the human genome. Many HERV-K proviruses express a regulatory protein Rec, which binds to an element present in HERV-K mRNAs called the RcRE. Read More

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December 2019

An Alu Element Insertion in Intron 1 Results in Aberrant Alternative Splicing of APOBEC3G Pre-mRNA in Northern Pig-Tailed Macaques () That May Reduce APOBEC3G-Mediated Hypermutation Pressure on HIV-1.

J Virol 2020 01 31;94(4). Epub 2020 Jan 31.

Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Center for Biosafety Mega-Science, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China

APOBEC3 family members, particularly APOBEC3F and APOBEC3G, inhibit the replication and spread of various retroviruses by inducing hypermutation in newly synthesized viral DNA. Viral hypermutation by APOBEC3 is associated with viral evolution, viral transmission, and disease progression. In recent years, increasing attention has been paid to targeting APOBEC3G for AIDS therapy. Read More

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January 2020

Generation of a neutralizing antibody against RD114-pseudotyped viral vectors.

J Gen Virol 2020 09;101(9):1008-1018

Division of Infection and Immunity, University College London, Cruciform Building, Gower Street, WC1E 6BT, UK.

The feline endogenous RD114 glycoprotein has proved to be an attractive envelope to pseudotype both retroviral and lentiviral vectors. As a surface protein, its detection on packaging cells as well as viral particles would be useful in different fields of its use. To address this, we generated a monoclonal antibody against RD114 by immunization of rats, termed 22F10. Read More

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September 2020

Variable Baseline Endogenous Retrovirus (PcEV) Expression Is Upregulated in Acutely SIV-Infected Macaques and Correlated to STAT1 Expression in the Spleen.

Front Immunol 2019 15;10:901. Epub 2019 May 15.

School of Biomedical Sciences, Faculty of Medicine and Dentistry, University of Plymouth, Plymouth, United Kingdom.

Retroviral replication leaves a DNA copy in the host cell chromosome, which over millions of years of infection of germline cells has led to 5% of the human genome sequence being comprised of endogenous retroviruses (ERVs), distributed throughout an estimated 100,000 loci. Over time these loci have accrued mutations such as premature stop codons that prevent continued replication. However, many loci remain both transcriptionally and translationally active and ERVs have been implicated in interacting with the host immune system. Read More

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September 2020

Does HIV infection contribute to increased beta-amyloid synthesis and plaque formation leading to neurodegeneration and Alzheimer's disease?

J Neurovirol 2019 10 13;25(5):634-647. Epub 2019 Mar 13.

Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec, Canada.

HIV infection in the combination antiretroviral therapy (cART) era has become a chronic disease with a life expectancy almost identical to those free from this infection. Concomitantly, chronic diseases such as neurodegenerative diseases have emerged as serious clinical problems. HIV-induced cognitive changes, although clinically very diverse are collectively called HIV-associated neurocognitive disorder (HAND). Read More

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October 2019

Creation of versatile cloning platforms for transgene expression and dCas9-based epigenome editing.

Nucleic Acids Res 2019 02;47(4):e23

Sarah W. Stedman Nutrition and Metabolism Center, Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA.

Genetic manipulation via transgene overexpression, RNAi, or Cas9-based methods is central to biomedical research. Unfortunately, use of these tools is often limited by vector options. We have created a modular platform (pMVP) that allows a gene of interest to be studied in the context of an array of promoters, epitope tags, conditional expression modalities, and fluorescent reporters, packaged in 35 custom destination vectors, including adenovirus, lentivirus, PiggyBac transposon, and Sleeping Beauty transposon, in aggregate >108,000 vector permutations. Read More

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February 2019

HIV-1 Vpr and p21 restrict LINE-1 mobility.

Nucleic Acids Res 2018 09;46(16):8454-8470

Center for AIDS Research, Kumamoto University, Kumamoto 860-0811, Japan.

Long interspersed element-1 (LINE-1, L1) composes ∼17% of the human genome. However, genetic interactions between L1 and human immunodeficiency virus type 1 (HIV-1) remain poorly understood. In this study, we found that HIV-1 suppresses L1 retrotransposition. Read More

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September 2018

Integration Mapping of piggyBac-Mediated CD19 Chimeric Antigen Receptor T Cells Analyzed by Novel Tagmentation-Assisted PCR.

EBioMedicine 2018 Aug 3;34:18-26. Epub 2018 Aug 3.

Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan. Electronic address:

Insertional mutagenesis is an important risk with all genetically modified cell therapies, including chimeric antigen receptor (CAR)-T cell therapy used for hematological malignancies. Here we describe a new tagmentation-assisted PCR (tag-PCR) system that can determine the integration sites of transgenes without using restriction enzyme digestion (which can potentially bias the detection) and allows library preparation in fewer steps than with other methods. Using this system, we compared the integration sites of CD19-specific CAR genes in final T cell products generated by retrovirus-based and lentivirus-based gene transfer and by the piggyBac transposon system. Read More

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HIV-1 inhibition in cells with CXCR4 mutant genome created by CRISPR-Cas9 and piggyBac recombinant technologies.

Sci Rep 2018 06 5;8(1):8573. Epub 2018 Jun 5.

School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, P.R. China.

The C-X-C chemokine receptor type 4 (CXCR4) is one of the major co-receptors for human immunodeficiency virus type 1 (HIV-1) entry and is considered an important therapeutic target. However, its function in maintaining the development of hematopoietic stem cells (HSC) makes it difficult to be used for HIV-1 gene therapy with HSC transplantation. A previous report showed that the natural CXCR4 P191A mutant inhibits HIV-1 infection without any defect in HSC differentiation, which could provide a basis for the development of new approaches for HIV-1 gene therapy. Read More

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Time-Restricted PiggyBac DNA Transposition by Transposase Protein Delivery Using Lentivirus-Derived Nanoparticles.

Mol Ther Nucleic Acids 2018 Jun 30;11:253-262. Epub 2018 Mar 30.

Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark. Electronic address:

Continuous innovation of revolutionizing genome engineering technologies calls for an intensified focus on new delivery technologies that not only match the inventiveness of genome editors but also enable the combination of potent delivery and time-restricted action of genome-modifying bits and tools. We have previously demonstrated the use of lentivirus-derived nanoparticles (LNPs) as a protein delivery vehicle, incorporating and transferring DNA transposases, designer nucleases, or RNA-guided endonucleases fused to the N terminus of the Gag/GagPol polypeptide. Here, we establish LNP-directed transfer of the piggyBac DNA transposase protein by fusing the transposase to the integrase protein in the C-terminal end of GagPol. Read More

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Transcriptional Modulation of Human Endogenous Retroviruses in Primary CD4+ T Cells Following Vorinostat Treatment.

Front Immunol 2018 12;9:603. Epub 2018 Apr 12.

Faculty of Medicine, University of Southampton, Southampton, Hants, United Kingdom.

The greatest obstacle to a cure for HIV is the provirus that integrates into the genome of the infected cell and persists despite antiretroviral therapy. A "shock and kill" approach has been proposed as a strategy for an HIV cure whereby drugs and compounds referred to as latency-reversing agents (LRAs) are used to "shock" the silent provirus into active replication to permit "killing" by virus-induced pathology or immune recognition. The LRA most utilized to date in clinical trials has been the histone deacetylase (HDAC) inhibitor-vorinostat. Read More

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A new approach to CAR T-cell gene engineering and cultivation using piggyBac transposon in the presence of IL-4, IL-7 and IL-21.

Cytotherapy 2018 04 21;20(4):507-520. Epub 2018 Feb 21.

Institute of Hematology and Blood Transfusion, Prague, Czech Republic; Department of Hematology, First Faculty of Medicine and General University Hospital, Prague, Czech Republic. Electronic address:

Background Aims: Clinical-grade chimeric antigenic receptor (CAR)19 T cells are routinely manufactured by lentiviral/retroviral (LV/RV) transduction of an anti-CD3/CD28 activated T cells, which are then propagated in a culture medium supplemented with interleukin (IL)-2. The use of LV/RVs for T-cell modification represents a manufacturing challenge due to the complexity of the transduction approach and the necessity of thorough quality control.

Methods: We present here a significantly improved protocol for CAR19 T-cell manufacture that is based on the electroporation of peripheral blood mononuclear cells with plasmid DNA encoding the piggyBac transposon/transposase vectors and their cultivation in the presence of cytokines IL-4, IL-7 and IL-21. Read More

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An Efficient In Vitro Transposition Method by a Transcriptionally Regulated Sleeping Beauty System Packaged into an Integration Defective Lentiviral Vector.

J Vis Exp 2018 01 12(131). Epub 2018 Jan 12.

Centre for Regenerative Medicine, Department of Life Sciences, University of Modena and Reggio Emilia;

The Sleeping Beauty (SB) transposon is a non-viral integrating system with proven efficacy for gene transfer and functional genomics. To optimize the SB transposon machinery, a transcriptionally regulated hyperactive transposase (SB100X) and T2-based transposon are employed. Typically, the transposase and transposon are provided transiently by plasmid transfection and SB100X expression is driven by a constitutive promoter. Read More

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January 2018

A Mos1 transposase in vivo assay to screen new HIV-1 integrase inhibitors.

Genetica 2018 Apr 19;146(2):243-247. Epub 2018 Jan 19.

Department of Biochemistry and Molecular Biology, CCNE, Federal University of Santa Maria (UFSM), Av. Roraima 1000, Camobi, Santa Maria, RS, 97105-900, Brazil.

The integrase and transposase enzymes of retrovirus and transposons, respectively, share the catalytic DDE domain. In vitro assays showed that inhibitors of HIV-1 integrase generally inhibit the mariner Mos1 transposase. Using a Drosophila strain in which the mobilisation of the mariner element can be quantified by mosaic eyes, we showed that flies maintained in medium containing 210 µM to 4 mM of raltegravir, or 1 or 2 mM of dolutegravir, which are HIV-1 integrase inhibitor used in AIDS treatment, have 23-33% less somatic mobilisation in mosaic eyes when treated with raltegravir and 28-32% when treated with dolutegravir. Read More

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Biochemical Basis of APOBEC3 Deoxycytidine Deaminase Activity on Diverse DNA Substrates.

ACS Infect Dis 2018 03 9;4(3):224-238. Epub 2018 Feb 9.

Department of Microbiology and Immunology, College of Medicine , University of Saskatchewan , 107 Wiggins Road , Saskatoon , Saskatchewan S7N 5E5 , Canada.

The Apolipoprotein B mRNA editing complex (APOBEC) family of enzymes contains single-stranded polynucleotide cytidine deaminases. These enzymes catalyze the deamination of cytidine in RNA or single-stranded DNA, which forms uracil. From this 11 member enzyme family in humans, the deamination of single-stranded DNA by the seven APOBEC3 family members is considered here. Read More

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HIV-1 Infection of Primary CD4 T Cells Regulates the Expression of Specific Human Endogenous Retrovirus HERV-K (HML-2) Elements.

J Virol 2018 01 14;92(1). Epub 2017 Dec 14.

Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA

Endogenous retroviruses (ERVs) occupy extensive regions of the human genome. Although many of these retroviral elements have lost their ability to replicate, those whose insertion took place more recently, such as the HML-2 group of HERV-K elements, still retain intact open reading frames and the capacity to produce certain viral RNA and/or proteins. Transcription of these ERVs is, however, tightly regulated by dedicated epigenetic control mechanisms. Read More

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January 2018

Lentiviral gene delivery to plasmolipin-expressing cells using Mus caroli endogenous retrovirus envelope protein.

Biochimie 2017 Nov 11;142:226-233. Epub 2017 Sep 11.

Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya St, 16/10, Moscow, 117997, Russia; National Research Tomsk Polytechnic University, 30 av. Lenina, Tomsk, 634050, Russia.

Gene therapy is a promising method for treating malignant diseases. One of the main problems is target delivery of therapeutic genes. Here we show that lentiviral vector particles pseudotyped with Mus caroli endogenous retrovirus (McERV) envelope protein can be used for selective transduction of PLLP-expressing cells. Read More

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November 2017

Integrating Vectors for Gene Therapy and Clonal Tracking of Engineered Hematopoiesis.

Hematol Oncol Clin North Am 2017 10;31(5):737-752

Institute of Experimental Hematology, REBIRTH Cluster of Excellence, Hannover Medical School, Carl Neuberg Strasse 1, 30625 Hannover, Germany; Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA. Electronic address:

Gene therapy using autologous or allogeneic cells offers promising possibilities to treat inherited and acquired diseases, ideally leading to a long-lasting therapeutic correction. This article summarizes efforts that use integrating vectors derived from retroviruses and transposons, and briefly explains integrating vector biology and integration site analysis and recent successful application of this technology in clinical trials. Moreover, outlined is how these vectors can be used for cancer gene discovery and clonal tracking of benign and malignant hematopoiesis to gain insights into the dynamics of hematopoiesis. Read More

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October 2017

The Short Isoform of BRD4 Promotes HIV-1 Latency by Engaging Repressive SWI/SNF Chromatin-Remodeling Complexes.

Mol Cell 2017 Sep 24;67(6):1001-1012.e6. Epub 2017 Aug 24.

Gladstone Institutes, University of California, San Francisco, San Francisco, CA 94158, USA; Graduate Program in Pharmaceutical Sciences and Pharmacogenomics, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Medicine, University of California, San Francisco, San Francisco, CA 94158, USA. Electronic address:

BET proteins commonly activate cellular gene expression, yet inhibiting their recruitment paradoxically reactivates latent HIV-1 transcription. Here we identify the short isoform of BET family member BRD4 (BRD4S) as a corepressor of HIV-1 transcription. We found that BRD4S was enriched in chromatin fractions of latently infected T cells, and it was more rapidly displaced from chromatin upon BET inhibition than the long isoform. Read More

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September 2017

Anti-HERV-K (HML-2) capsid antibody responses in HIV elite controllers.

Retrovirology 2017 Aug 22;14(1):41. Epub 2017 Aug 22.

Division of Experimental Medicine, Department of Medicine, University of California, San Francisco, San Francisco, CA, USA.

Background: Human endogenous retroviruses (HERVs) comprise approximately 8% of the human genome and while the majority are transcriptionally silent, the most recently integrated HERV, HERV-K (HML-2), remains active. During HIV infection, HERV-K (HML-2) specific mRNA transcripts and viral proteins can be detected. In this study, we aimed to understand the antibody response against HERV-K (HML-2) Gag in the context of HIV-1 infection. Read More

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A noncoding RNA containing a SINE-B1 motif associates with meiotic metaphase chromatin and has an indispensable function during spermatogenesis.

PLoS One 2017 28;12(6):e0179585. Epub 2017 Jun 28.

Department of Physiology, Keio University School of Medicine, 35 Shinamomachi, Shinjuku-ku, Tokyo, Japan.

A search for early response genes that are activated following germ cell induction from mouse embryonic stem cells in vitro led us to the isolation of a long noncoding RNA that contains a SINE (short interspersed element)-B1F motif that was named R53. In situ hybridization and northern blot analyses revealed that the R53 subfragment RNA bears a B1F motif, is processed from the primary transcript, is expressed in adult testis and is predominantly localized in meiotic metaphase chromatin during spermatogenesis. Recent studies of chromosome-associated RNAs have explored novel functions of noncoding RNAs. Read More

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September 2017