Final answer:
The envelope plasmid used in lentivirus production carries genes for envelope proteins, crucial for viral entry into host cells. It enables the lentivirus to acquire a lipid bilayer from the host, containing necessary glycoproteins for cell targeting in gene therapy.
Step-by-step explanation:
The envelope plasmid used in lentivirus production is a key component in the generation of recombinant lentiviral vectors. Lentiviruses, such as HIV, are a class of enveloped viruses that generate virions surrounded by a phospholipid bilayer known as a viral envelope, using the host cell's membrane. The envelope plasmid encodes the viral envelope proteins, like the glycoproteins, which are crucial for the virus' ability to fuse with and enter host cells. During the assembly of lentiviral vectors, an envelope plasmid is used to produce the fusion proteins required for the virus to infect target cells effectively.
The viral envelope that is acquired during the budding process includes not only the proteins that are coded by the viral genome but also host cell proteins. The lipid bilayer of the envelope is entirely derived from the host cell. This mimics the natural process observed in the production of enveloped viruses, such as influenza, HIV, and cytomegalovirus, where the viruses envelop themselves with a portion of the host's cell membrane as they exit the host cell.
In the case of producing lentiviral vectors, the envelope plasmid is crucial as it provides the necessary genetic information to create an envelope that can mediate targeting and entry into specific types of cells. This specificity is key in therapeutic applications where it is necessary to deliver genetic material to particular cells with minimal off-target effects.