Prokaryotic Expression of VP7 Gene and Subunit Vaccine Preparation of Bovine Rotavirus

Rotaviruses, approximately 70nm diameter in size, are classified into at least eight different groups according to the serological reactivity and genetic variability of VP6 [4] , and consist of three capsid layers including the outer structural proteins (VP7 and VP4), middle structural protein (VP6) and inner core structural proteins (VP 1, 2 and 3). VP4 (encoded by gene segment 4) and VP7 (encoded by gene segment 7, 8 or 9 depending on the strain), both of which are independently responsible for virus neutralization [5, 6]. The neutralization specificity related to VP7 is referred to as the G serotype (for glycoprotein), and that associated with VP4 is referred to as the P serotype (for protease-sensitive protein) [7]. Up to date, the rotavirus species comprises at least 27 G types (according to the nt sequence of VP7) and 37 P types (according to the nt sequence of VP4) [8, 9].