| The single stranded RNA is tightly bound to nucleocapsid proteins, p7 and enzymes needed for the development of the virion such as reverse transcriptase, proteases, ribonuclease and integrase. |
| The DNA is enclosed in a nucleocapsid, or core antigen, which is surrounded by a spherical envelope. |
| Surrounding the nucleocapsid is an outer lipid envelope made from the membrane of the host cell. |
| In some viral families, the nucleocapsid is surrounded by a peripheral optional structure called the envelope. |
| The nucleoprotein structure defined by the nucleic acid and the internal proteins is called nucleoid and the group nucleoid and capsid constitute a functional unity which is called nucleocapsid. |
| The RNA-binding motif is a characteristic feature of the nucleocapsid and is widespread among retroelements. |
