Why are retroviruses important?
Retroviruses are the subject of extensive research in virology these days for several reasons. The first is that retroviruses have been linked to cancer, and more aspects of the relationship between viruses and cancer are discovered every day. The second is that human immunodeficiency virus (HIV) is a retrovirus. HIV is the causative agent of the disease acquired immunodeficiency syndrome(AIDS). The search for AIDS treatments and a definitive cure remains one ofthe primary goals of retroviral research. HIV will be covered more extensively in the Hot Topics Magazine. The third is that retroviruses can be used in gene therapy, as described in the following Biochemical Connections box.
All retroviruses have certain genes in common. There is a gene for proteins of the nucleocapsid, often called coat proteins (CP). They all have a gene for reverse transcriptase (RT), and they all have genes for envelope proteins (EP).
Figure 14.9 shows a schematic of the RNA genomes of common retroviruses. In the case of the Rous sarcoma virus, the genome also contains an oncogene that causes tumors.