The Interactions of Retroviruses and their Hosts

Excerpt

Retroviruses are small in the genetic sense, having genomes that are only about 10 kb in length, and a correspondingly small complement of virion proteins (Chapter 2). A virus that carries such a small complement of genetic information depends heavily on the host cell for essential replication functions. To replicate, retroviruses have a number of simple and direct requirements, most of which have already been discussed in the first seven chapters. First, the host cell must express a specific receptor on its surface to provide a site for the virus to bind and trigger the entry process, mediated by the viral Env protein (Chapter 3). Second, the cell must supply deoxynucleotides in adequate concentration for the virion reverse transcriptase to transform the RNA genome into DNA (Chapter 4). Third, there must be a means for the viral DNA to access host chromosomes as targets for viral integration; integration may also require the aid of host repair enzymes (Chapter 5). Fourth, host machinery and components are necessary to express viral RNA and carry out the processing (polyadenylation and splicing) and transport of both viral genomic and messenger RNA to the cytoplasm (Chapter 6). Finally, host cell machinery is necessary for the synthesis, folding, modification, and transport of viral proteins to the membrane assembly sites (Chapter 7).