Search results for "Long terminal repeat"
showing 10 items of 14 documents
The gypsy database (GyDB) of mobile genetic elements: release 2.0
2011
This article introduces the second release of the Gypsy Database of Mobile Genetic Elements (GyDB 2.0): a research project devoted to the evolutionary dynamics of viruses and transposable elements based on their phylogenetic classification (per lineage and protein domain). The Gypsy Database (GyDB) is a long-term project that is continuously progressing, and that owing to the high molecular diversity of mobile elements requires to be completed in several stages. GyDB 2.0 has been powered with a wiki to allow other researchers participate in the project. The current database stage and scope are long terminal repeats (LTR) retroelements and relatives. GyDB 2.0 is an update based on the analys…
ICTV Virus Taxonomy Profile: Metaviridae
2020
Metaviridae is a family of retrotransposons and reverse-transcribing viruses with long terminal repeats belonging to the order Ortervirales. Members of the genera Errantivirus and Metavirus include, respectively, Saccharomyces cerevisiae Ty3 virus and its Gypsy-like relatives in drosophilids. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the family Metaviridae, which is available at ictv.global/report/metaviridae.
ICTV Virus Taxonomy Profile: Pseudoviridae
2021
Pseudoviridae is a family of reverse-transcribing viruses with long terminal repeats (LTRs) belonging to the order Ortervirales. Pseudoviruses are commonly found integrated in the genomes of diverse plants, fungi and animals and are broadly known as Ty1/Copia LTR retrotransposons. Inside the cell, they form icosahedral virus particles, but unlike most other viruses, do not have an extracellular phase. This is a summary of the ICTV Report on the family Pseudoviridae, which is available at ictv.global/report/pseudoviridae.
ICTV Virus Taxonomy Profile: Belpaoviridae 2021
2021
The family Belpaoviridae comprises metazoan-infecting reverse-transcribing viruses with long terminal repeats, commonly known as Bel/Pao LTR retrotransposons. These viruses share evolutionary history and genes involved in genome replication and virion formation with reverse-transcribing viruses of the families Metaviridae, Pseudoviridae, Retroviridae and Caulimoviridae. These five families form the order Ortervirales. This is a summary of the ICTV Report on the family Belpaoviridae, which is available at ictv.global/report/belpaoviridae.
Reverse-transcribing viruses (Belpaoviridae, Metaviridae, and Pseudoviridae)
2021
Fourth Edition.
Acute Nonlymphocytic Leukemia in Adults: Pathophysiology, Status of Current Therapy, and New Approaches
1987
Recent information concerning the cell biology of leukemias has provided new insights into the pathophysiology and pathogenesis of acute leukemia, involving the detection of leukemia viruses, oncogenes and their products, and the discovery of factors supporting clonal leukemic growth. Murine, avian, and cat leukemia viruses are well characterized. To date, only HTLV I appears to be a likely candidate as a human leukemia virus. For both avian and murine viruses, there is a fundamental classification distinction between long-latency viruses (LLV) and acute transforming viruses (ATV). The ATV are replication defective and must be propagated with a helper virus. They have within their genome an…
Protection of HeLa‐T4 + cells against human immunodeficiency virus (HIV) infection after stable transfection with HIV LTR‐2‘,5‘‐oligoadenylate synthe…
1990
An expression vector (pU3R-III/2-5AS) of human 2',5'-oligoadenylate (2-5A) synthetase was constructed in which a cDNA encoding an active form of the enzyme was located 3' to a 3'-long terminal repeat (LTR) of human immunodeficiency virus type 1 (HIV-1). The LTR-directed expression of this hybrid DNA could be activated in trans by the HIV tat gene product. This vector was used for transfection of HeLa-T4+ cells, which are permissive to HIV infection, as well as of normal HeLa cells. HIV replication after infection of the CD4-receptor-bearing HeLa-T4+ cells with HIV-1 was found to be strongly reduced when drug-selected cells cotransfected with pU3R-III/2-5AS and a hygromycin B resistance gene…
Network dynamics of eukaryotic LTR retroelements beyond phylogenetic trees
2009
Abstract Background Sequencing projects have allowed diverse retroviruses and LTR retrotransposons from different eukaryotic organisms to be characterized. It is known that retroviruses and other retro-transcribing viruses evolve from LTR retrotransposons and that this whole system clusters into five families: Ty3/Gypsy, Retroviridae, Ty1/Copia, Bel/Pao and Caulimoviridae. Phylogenetic analyses usually show that these split into multiple distinct lineages but what is yet to be understood is how deep evolution occurred in this system. Results We combined phylogenetic and graph analyses to investigate the history of LTR retroelements both as a tree and as a network. We used 268 non-redundant …
(2'-5')Oligoadenylate and intracellular immunity against retrovirus infection.
1992
1. 1. The double-stranded RNA-dependent 2′,5′-oligoadenylate (2–5A) synthetase/ribonuclease L (RNase L) system plays an essential role in the establishment of the antiviral state of a cell exposed to virus infection. 2. 2. Until recently, the application of 2–5A derivatives to reinforce this system seemed to be limited mainly due to the low specificity of RNase L for viral RNA. 3. 3. Two new strategies have been developed which yield a selective antiviral effect of 2–5As at least against human immunodeficiency virus-1 (HIV-1) infection: (i) an “intracellular immunization” appproach using 2-5A synthetase cDNA linked to HIV trans -acting response element (TAR) and (ii) inhibition of retrovira…
Interaction of 68–kDa TAR RNA-binding protein and other cellular proteins with rpion protein-RNA stem-loop
1995
The RNA stem-loop structure of the trans-activating region TAR sequence of human immunodeficiency virus-1 mRNA is the binding site for a number of host cell proteins. A virtually identical set of proteins from HeLa nuclear extracts was found to bind to the predicted RNA hairpin element of prion protein (PrP) mRNA, as demonstrated in UV cross-linking/RNase protection and Northwestern assays. We show that the cellular TAR loop-binding protein, p68, is among those proteins which associate with PrP RNA. Competition experiments with various TAR RNA mutants revealed that binding of partially purified p68 to PrP RNA stem-loop occurs sequence-specifically. The 100-kDa 2-5A synthetase which is invol…