Certain viruses contain a<unk> , which is a cluster of non-essential and essential proteins that line the space between the envelope and nucleocapsid of many enveloped viruses.  The<unk>  generally contains proteins that aid in viral replication and evasion of the immune response, typically with the signaling and activation of interferon.  Hence the<unk>  is usually released shortly after infection into the cytoplasm.  These proteins are usually formed within the late phase of the viral infectious cycle, after viral genes have been replicated.  Much information regarding<unk> s have been gathered from studying Herpes Simplex Virus.
Viral tegument
Viral envelope
Electron shell
Capsid
Vector 
Vector
Transfer RNA
Viral vector