Physical interaction between the membrane (M) and envelope (E) proteins of the coronavirus avian infectious bronchitis virus (IBV).

Abstract

Coronavirus avian infectious bronchitis virus (IBV) encodes at least four structural proteins, i.e. the nucleocapsid (N), membrane (M), spike (S) and envelope (E) proteins. The IBV E protein was first identified in 1990 (Liu et. al., 1990) and demonstrated to be associated with the virion envelope (Liu and Inglis, 1991). Several studies on the two other members of the Coronavirus family, namely Mouse Hepatitis Virus (MHV) and Transmissible Gastroenteritis Virus (TGEV), have indicated that E is likely to play a crucial role in viral assembly (Fischer et. al., 1998; Baudoux et. al., 1998). Together with M, E was demonstrated to be the minimal machinery required for the formation of Virus-Like Particles (VLPs) (Vennema et al, 1996). Recent reports took a step further in demonstrating that expression of E alone could lead to the release of VLPs (Maeda et. al., 1999; Raamsman et. al., 2000; Corse and Machamer, 2000).