All the viruses contain a nucleic acid enclosed in a protein coat.
These particles lack cytoplasm. The nucleic acid present in the viruses can be either DNA or RNAand their genome is either linear or circular; single-stranded or double-stranded. Depending on their symmetry, viruses are characterized byhelical, icosahedral, binal, and polymorphic. Além disso todos têm a capacidade de infectar linfócitos através do receptor CD4.
O vírus da Imunodeficiência símia SIV presente com muita freqüência nos macacos verdes africanos é muito próximo ao HIV-2, sugerindo que ambos evoluíram de uma origem comum.
Nos Retrovírus, salientam-se dois grupos com repercussões patológicas nos humanos: HTLV-1, 2 e Lentivirinae. Distinguem-se, Virus, portanto, duas fases da doença: Os pontos de entrada do vírus incluem o sangue, a pele e as mucosas do cólon, reto e órgao genital feminino. Fase de latência clínica, sem qualquer sinal Lentivirinae sintoma, podendo apenas persistir uma linfadenopatia generalizada. Herpes zoster e simplex com clínica exuberante, persistindo anormalmente durante longos períodos e consistindo Retrovirus vezes em lesões Classe e ulceradas com quantidades substanciais de vírusEpstein-Barr e CMV.
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 aprender preciso O para HTML? que e a specific gene using RNA interference technology in high-throughput formats. These studies can be a precursor to the development of novel drugs which aim to block a gene-product to treat diseases.
Conversely, lentivirus are also used to stably over-express certain genes, thus allowing researchers to examine the effect of increased gene expression in a model system.
Another common application is to use a lentivirus to introduce a new gene into human or animal cells. For example, a model of mouse hemophilia is corrected by expressing wild-type platelet- factor VIIIthe gene that is mutated in human hemophilia. Lentiviruses have also been successfully used for transduction of diabetic mice with the gene encoding PDGF platelet-derived growth factor 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.
Gammaretroviral and lentiviral vectors have so far been used in more than clinical trials, addressing treatment options for various diseases. Reverse transcription refers to the opposite of the normal transcription process that involves the synthesis of RNA from DNA. Retroviruses rely on the enzyme reverse transcriptase to perform this reverse transcription of its genome, which is then integrated into the host's genome with the use of an integrase enzyme.
The viral genes become part of the cell for its entire lifetime and reproduce as the host cell reproduces. Therefore, infections caused by viruses are usually lifelong. Retroviruses are enveloped viruses, meaning they have an outer layering derived from the membrane of its host cell. This outer lipid layer is studded with proteins coded for by the viral genome and host genome, although the lipid membrane itself is host-coded.
It offers protection from harmful agents and the proteins may include glycoproteins that help healthy cells to recognize the invaders as "friendly," helping their uptake. Characteristics of the outer envelope have a major effect on what types of cells the virus can attack.
Antibodies, which are created to prevent and fight viruses, are produced against the envelope and are found in vaccines. Retroviruses have a diameter of approximately nanometers.
All or part of this article may be confusing or unclear. Please help clarify the article. Suggestions may be on the talk page. Alpharetrovirus Avian leukosis virus, Rous sarcoma virus - Betaretrovirus Mouse mammary tumour virus - Gammaretrovirus Murine leukemia virusAbelson murine leukemia virus, Feline leukemia virus - Deltaretrovirus Human T-lymphotropic virus - Epsilonretrovirus.
It uses material from the Wikipedia article "Lentivirus".