Lentivirus (lenti-, Latin for "slow") is a genus of slow viruses of the Retroviridae family, characterized by a long incubation period. Lentiviruses can deliver a significant amount of genetic information into the DNA of the host cell, so they are one of the most efficient methods of a gene delivery vector. HIV, SIV, and FIV are all examples of lentiviruses. Virus classification involves naming and placing viruses into a taxonomic system. ... ss-RNA RT is the single stranded Ribonucleic acid genome that is present in the HIV virus. ... Genera Alpharetrovirus Betaretrovirus Gammaretrovirus Deltaretrovirus Epsilonretrovirus Lentivirus Spumavirus A retrovirus is a virus which has a genome consisting of two identical plus sense RNA molecules. ... This article or section does not cite any references or sources. ... Feline immunodeficiency virus (FIV) is a lentivirus that affects domesticated housecats worldwide. ... The human immunodeficiency virus (HIV) is a frequently mutating retrovirus that attacks the human immune system and which has been shown to cause acquired immune deficiency syndrome (AIDS). ... To meet Wikipedias quality standards, this article or section may require cleanup. ... For other uses, see Genus (disambiguation). ... Groups I: dsDNA viruses II: ssDNA viruses III: dsRNA viruses IV: (+)ssRNA viruses V: (-)ssRNA viruses VI: ssRNA-RT viruses VII: dsDNA-RT viruses A virus (from the Latin noun virus, meaning toxin or poison) is a microscopic particle (ranging in size from 20 - 300 nm) that can infect the... Genera Alpharetrovirus Betaretrovirus Gammaretrovirus Deltaretrovirus Epsilonretrovirus Lentivirus Spumavirus A retrovirus is a virus which has a genome consisting of two identical plus sense RNA molecules. ... In biological classification, family (Latin: familia, plural familiae) is 1) a rank or 2) a taxon in that rank. ... Incubation period is the time elapsed between exposure to a pathogenic organism and when symptoms and signs are first apparent. ... DNA, the molecular basis for inheritance. ... The structure of part of a DNA double helix Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions for the development and function of living organisms. ... In biology, a host is an organism that harbors a parasite, mutual partner, or commensal partner, typically providing nourishment and shelter. ... In epidemiology, a vector is an organism that does not cause disease itself but which spreads infection by conveying pathogens from one host to another. ... The human immunodeficiency virus (HIV) is a frequently mutating retrovirus that attacks the human immune system and which has been shown to cause acquired immune deficiency syndrome (AIDS). ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Feline immunodeficiency virus (FIV) is a lentivirus that affects domesticated housecats worldwide. ...

Classification

Five serogroups of lentiviruses are recognized, reflecting the vertebrate hosts with which they are associated (primates, sheep and goats, horses, cats, and cattle). The primate lentiviruses are distinguished by the use of CD4 protein as receptor and the absence of dUTPase. Some groups have cross-reactive gag antigens (e.g., the ovine, caprine and feline lentiviruses). Antibodies to gag antigens in lions and other large felids indicate the existence of other viruses related to FIV and the ovine/caprine lentiviruses. Description is on taxonomic level of genus. Families 15, See classification A primate is any member of the biological order Primates, the group that contains all the species commonly related to the lemurs, monkeys, and apes, with the latter category including humans. ... CD4 (cluster of differentiation 4) is a molecule that is expressed on the surface of T helper cells (as well as regulatory T cells and dendritic cells). ... A receptor in immunology is a molecule on the surface of an immunocyte (a cell of the immune system) which binds its ligand (a molecule of some sort; from Latin ligandum, an item which is to be bound). ... Group-specific antigen is the genetic material that codes for the core structural proteins of a retrovirus. ... An antigen is any molecule that is recognized by antibodies. ... ... Genera Subfamily Caprinae   Nemorhaedus   Rupicapra   Oreamnos   Budorcas   Ovibos   Pseudonovibos   Hemitragus   Ammotragus   Pseudois   Capra   Ovis Subfamily Pantholopinae   Pantholops A goat antelope is any of the species of mostly medium-sized bovids that make up the subfamily Caprinae or the single species in subfamily Pantholopinae. ... “Feline” redirects here. ... Wikipedia does not yet have an article with this exact name. ... Taxonomy (from Greek ταξινομία from the words taxis = order and nomos = law) may refer to either a hierarchical classification of things, or the principles underlying the classification. ...

Morphology

Virions enveloped; slightly pleomorphic; spherical; 80-100 nm in diameter. Surface projections of envelope small (surface appears rough), or barely visible; spikes (of about 8nm); dispersed evenly over all the surface. Nucleocapsids (cores) isometric. Nucleoid concentric and rod-shaped, or shaped like a truncated cone. A common alternate meaning of virus is computer virus. ... This page is a candidate to be copied to Wiktionary. ... Many viruses (e. ... A peplomer is a glycoprotein spike on a viral capsid. ... A Nucleocapsid is the genome (DNA or RNA) of a virus and the protein coat surrounding it (the capsid). ... Look up isometric in Wiktionary, the free dictionary. ... It has been suggested that Genophore be merged into this article or section. ...

Genome Organization and Replication

Features of the genome: infectious viruses have 3 main genes coding for the viral proteins in the order: 5´-gag-pol-env-3´. There are additional genes depending on the virus (e.g., for HIV-1: vif, vpr, vpu, tat, rev, nef) whose products are involved in regulation of synthesis and processing viral RNA and other replicative functions. The LTR is about 600nt long, of which the U3 region is 450, the R sequence 100 and the U5 region some 70 nt long.

Viral proteins involved in early stages of replication include Reverse Transcriptase and Integrase. Reverse Transcriptase (RT) is the virally encoded RNA-dependent DNA polymerase. The enzyme uses the viral RNA genome as a template for the synthesis of a complementary DNA copy. RT also has RNaseH activity for destruction of the RNA-template. Integrase (IN) binds both the viral cDNA generated by RT and the host DNA. Processing of the LTR by IN is performed prior to insertion of the viral genome into the host DNA.

Although transmission is generally via infectious particles, lentiviruses are capable of infecting neighboring cells in direct contact with the host cells, without having to form extracellular particles.

Antigenic Properties

Serological Relationships: Antigen determinants are type-specific and group-specific. Antigen determinants that possess type-specific reactivity are found on the envelope. Antigen determinants that possess type-specific reactivity and are involved in antibody mediated neutralization are found on the glycoproteins. Cross-reactivity has been found among some species of the same serotype, but not between members of different genera. Classification of members of this taxon is infrequently based on their antigenic properties. A glycoprotein is a macromolecule composed of a protein and a carbohydrate (a sugar). ... A taxon (plural taxa), or taxonomic unit, is a grouping of organisms (named or unnamed). ...

Biological

• Symptoms and Host Range: Host of virus belongs to the Domain Eucarya. Host of virus belongs to the Kingdom Animalia. Phylum Chordata. Subphylum Vertebrata. Class Mammalia. Order Primates, Perissodactyla, Carnivora, and Artiodactyla.

• Transmission: Transmitted by means not involving a vector.

• Geographic Distribution: World-wide.

In biology, a domain (also superregnum, superkingdom, or empire) is the top-level grouping of organisms in scientific classification, higher than a kingdom. ... Kingdoms Eukaryotes are organisms with complex cells, in which the genetic material is organized into membrane-bound nuclei. ... Phyla Subkingdom Parazoa Porifera (sponges) Subkingdom Agnotozoa Placozoa Orthonectida Rhombozoa Subkingdom Metazoa Radiata Cnidaria Ctenophora - Comb jellies Bilateria Protostomia Acoelomorpha Platyhelminthes - Flatworms Nemertina - Ribbon worms Gastrotricha Gnathostomulida - Jawed worms Micrognathozoa Rotifera - Rotifers Acanthocephala Priapulida Kinorhyncha Loricifera Entoprocta Nematoda - Roundworms Nematomorpha - Horsehair worms Cycliophora Mollusca - Mollusks Sipuncula - Peanut worms Annelida - Segmented... Typical Classes Subphylum Urochordata - Tunicates Ascidiacea Thaliacea Larvacea Subphylum Cephalochordata - Lancelets Subphylum Myxini - Hagfishes Subphylum Vertebrata - Vertebrates Petromyzontida - Lampreys Placodermi (extinct) Chondrichthyes - Cartilaginous fishes Acanthodii (extinct) Actinopterygii - Ray-finned fishes Actinistia - Coelacanths Dipnoi - Lungfishes Amphibia - Amphibians Reptilia - Reptiles Aves - Birds Mammalia - Mammals Chordates (phylum Chordata) include the vertebrates, together with... Typical classes Petromyzontidae (lampreys) Placodermi - extinct Chondrichthyes (cartilaginous fish) Acanthodii - extinct Actinopterygii (ray-finned fish) Actinistia (coelacanths) Dipnoi (lungfish) Amphibia (amphibians) Reptilia (reptiles) Aves (birds) Mammalia (mammals) Vertebrata is a subphylum of chordates, specifically, those with backbones or spinal columns. ... Orders Subclass Monotremata Monotremata Subclass Marsupialia Didelphimorphia Paucituberculata Microbiotheria Dasyuromorphia Peramelemorphia Notoryctemorphia Diprotodontia Subclass Placentalia Xenarthra Dermoptera Desmostylia Scandentia Primates Rodentia Lagomorpha Insectivora Chiroptera Pholidota Carnivora Perissodactyla Artiodactyla Cetacea Afrosoricida Macroscelidea Tubulidentata Hyracoidea Proboscidea Sirenia The mammals are the class of vertebrate animals primarily characterized by the presence of mammary... For the ecclesiastical use of this term, see primate (religion) Families 13, See classification A primate is any member of the biological order Primates, the group that contains all lemurs, monkeys, and apes, including humans. ... Families Equidae Tapiridae Rhinocerotidae The odd-toed ungulates or Perissodactyla are large to very large browsing and grazing mammals with relatively simple stomachs and a large middle toe. ... Families 17, See classification The diverse order Carnivora (IPA: or IPA: ; from Latin carō (stem carn-) flesh, + vorāre to devour) includes over 260 placental mammals. ... Families Suidae Hippopotamidae Tayassuidae Camelidae Tragulidae Moschidae Cervidae Giraffidae Antilocapridae Bovidae The even-toed ungulates form the mammal order Artiodactyla. ... In medicine, transmission is the passing of a disease from an infected individual or group to a previously uninfected individual or group. ... In epidemiology, a vector is an organism that does not cause disease itself but which spreads infection by conveying pathogens from one host to another. ...

Physicochemical and Physical Properties

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• General
  • Buoyant density 1.16-1.18 g cm^-3 in sucrose
  • Virions sensitive to heat, detergents, and formaldehyde
  • Infectivity not affected by irradiation

Classed as having class c morphology Image File history File links Circle-question-red. ... In physics, buoyancy is an upward force on an object immersed in a fluid (i. ...

• Nucleic Acid
  • Virions contain 2 % nucleic acid
  • Genome consists of a dimer
  • Virions contain one molecule of (each) linear positive-sense single stranded RNA.
  • Total genome length is of one monomer 9200 nt
  • Genome sequence has terminal repeated sequences; long terminal repeats (LTR) (of about 600 nt
  • The 5' end of the genome has a cap
  • Cap sequence of type 1 m7G5ppp5'GmpNp
  • 3' end of each monomer has a poly (A) tract; 3'-terminus has a tRNA-like structure (and accepts lysin)
  • Encapsidated nucleic acid solely genomic
  • 2 copies packed per particle (held together by hydrogen bonds to form a dimer).
• Proteins 11
  • Virions contain 60 % protein
  • Five structural virion proteins found (major)
    • Protein size largest 120000 Da. Gp120 glycosylated surface envelope protein SU, encoded by the viral gene env
    • Protein size of 2nd largest 41000 Da. Gp41 glycosylated transmembrane envelope protein TM, also encoded by the viral gene env.
    • Protein size of 3rd largest 24000 Da. P24 non-glycosylated capsid protein CA.
    • Protein size of 4th largest 17000 Da. P17 non-glycosylated matrix protein MA.
    • Protein size of 5th largest 7000-11000 Da. Non-glycosylated capsid protein NC.
    • Proteins MA, CA and NC are all encoded by the gag gene. Virion structural proteins are glycosylated. Are the following: the envelope proteins SU and TM.
  • Usually four non-structural proteins found, or three non-structural proteins found (in the primate lentiviruses).
    • Protein size 66000 Da. Reverse transcriptase RT encoded by the pol gene.
    • Protein size of 2nd largest 32000 Da. Integrase IN also encoded by the pol gene.
    • Protein size of 3rd 14000 Da. Protease PR encoded by the pro gene. dUPTase DU, the role of which is still unknown.
• Lipids: Virions contain 35 % lipid.
• Carbohydrates: Other compounds detected in the particles 3% carbohydrates.

Look up nucleic acid in Wiktionary, the free dictionary. ... Look up nucleic acid in Wiktionary, the free dictionary. ... Figure 1: Basic lipid structure. ... Carbohydrates (literally hydrates of carbon) are chemical compounds that act as the primary biological means of storing or consuming energy, other forms being fat and protein. ...

Practical applications

Lentivirus is primarily a research tool used to introduce a gene product into in vitro systems or animal models. Large-scale collaborative efforts are underway to use lentiviruses to block the expression of a specific gene using RNA interference technology in high-throughput formats [1]. The expression of short-hairpin RNA (shRNA) reduces the expression of a specific gene, thus allowing researchers to examine the necessity and effects of a given gene in a model system. These studies can be a precursor to the development novel drugs which aim to block a gene-product to treat a disease.
Another common application is to use a lentivirus to introduce a new gene into human or animal cells. For example, a model of mouse hemophillia is corrected by expressing wild-type platlet-factor VIII, the gene that is mutated in human hemophillia [2]. Lentiviral infection have advantages over other gene-therapy methods including high-efficiency infection of dividing and non-dividing cells, long-term stable expression of a transgene, and low immunogenicity. Lentiviruses have also been successfully used for transfection of diabetic mice with the gene encoding PDGF (platelet-derived growth factor) [3], a therapy being considered for use in humans. These treatments, like most current gene therapy experiments, show promise but are yet to be established as safe and effective in controlled human studies. Wiktionary has a definition of: In vitro In vitro (Latin: within glass) means within a test tube, or, more generally, outside a living organism or cell. ... Cells use dicer to trim double stranded RNA to form small interfering RNA or microRNA. An exogenous dsRNA or endogenous pre-miRNA can be processed by dicer and incorporated into the RNA-induced silencing complex (RISC), which targets single-stranded messenger RNA molecules and triggers translational repression;[1] incorporation into... Introducing DNA into eukaryotic cells, such as animal cells, is called transfection. ... For a non-technical introduction to the topic, see Introduction to Genetics. ... Platelet-derived growth factor (PDGF) is one of the numerous proteins that regulate cell growth and division. ...

References

• Ryan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology, 4th ed., McGraw Hill. ISBN 0-8385-8529-9. 

External links

• ICTV taxonomy of Lentivirus
• A lentiviral gene delivery technology