 | This article focuses only on one specialized aspect of the subject. (January 2014) |
Group-specific antigen, or gag, is the polyprotein that contains the core structural proteins of an Ortervirus (except Caulimoviridae). It was named as such because scientists used to believe it was antigenic. Now it is known that it makes up the inner shell, not the envelope exposed outside. It makes up all the structural units of viral conformation and provides supportive framework for mature virion.
All orthoretroviral gag proteins are processed by the protease (PR or pro) into MA (matrix), CA (capsid), NC (nucleocapsid) parts, and sometimes more.[1] If Gag fails to cleave into its subunits, virion fails to mature and remains uninfective.
It comprises part of the gag-onc fusion protein.
- ^ Coffin JM, Hughes SH, Varmus HE (1997). "Genetic Organization". Retroviruses. Cold Spring Harbor Laboratory Press.