Abstract
Retroviral assembly proceeds through a series of concerted events that lead to the formation and release of infectious virion particles from the infected cell. Upon translation, structural proteins are targeted to the plasma membrane where they accumulate. There, the nascent particle forces the plasma membrane to form a bud, which pinches off releasing the virion particle from the cell. In this review we describe the molecular mechanisms now known to be behind the process of virion assembly. In particular, we focus on the human immunodeficiency virus type 1, the prototype member of the lentivirus subfamily of the Retroviridae.