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Retroviruses & HIV

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Retroviruses are a specialised type of virus, characterised by a unique mode of replication within the cells of their hosts. They contain a core of the nucleic acid RNA instead of the usual DNA. Unlike other RNA viruses, retroviruses replicate as DNA rather than RNA genomes inside their hosts by means of the enzyme, reverse transcriptase. Human Immunodeficiency Virus (HIV) is a retrovirus and upon infection, results in Acquired Immune Deficiency Syndrome (AIDS). ...read more.


In order to inject its genetic information into the host cell, the HIV must bind its envelope glycoprotein gp120 to molecules on the surface of the cell. Only cells that carry the appropriate molecules are susceptible to infection by HIV. Scientists have found that a molecule called CD4, which is found particularly on certain T-lymphocytes was the pirmary binding site but other co-receptors have since been discovered. ...read more.


The viral DNA enters the nucleus of the cell and is integrated into the cellular DNA. Normal cellular processes transcribe the integrated DNA into new virion RNA and viral messenger RNA, and translate the viral messenger RNA into new viral proteins. The proteins and the virion RNA are assembled into a new viral nucleoid, which buds off from the T-lymphocyte, taking a piece of the host cell's membrane for its envelope. Matthew Bonser ...read more.

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