Retroviridae

A retrovirus is a virus that inserts a DNA copy of its RNA genome into the DNA of a host cell that it invades, thus changing the genome of that cell. After invading a host cell's cytoplasm, the virus uses its own reverse transcriptase enzyme to produce DNA from its RNA genome, the reverse of the usual pattern, thus retro (backward). The new DNA is then incorporated into the host cell genome by an integrase enzyme, at which point the retroviral DNA is referred to as a provirus. The host cell then treats the viral DNA as part of its own genome, transcribing and translating the viral genes along

thumb|HIV Retrovirus Orthoretrovirinae is a subfamily of viruses belonging to Retroviridae, a family of enveloped viruses that replicate in a host cell through the process of reverse transcription. The subfamily currently includes six genera, of which Lentivirus contains the human immunodeficiency virus (HIV). These viruses cause a variety of tumors, malignancies and immune deficiency disease in humans and other mammals.