Table 4.3.

Characteristics of rotavirus structural and nonstructural proteins

Genome segment	Protein product	Mol. Wt. of protein (A0)	No. of molecules per virion	Location in virus particles	Function
1	VP1	125	<25	Core	RNA-dependent RNA polymerase; part of minimal replication complex
2	VP2	94	120	Core	Inner capsid structural protein; sequence nonspecific RNA binding activity; part of minimal replication complex
3	VP3	88	<25	Core	Guanylyltransferase; methyltransferase; part of virion transcription complex
4	VP4	86.7	120	Outer capsid spike	Dimers form outer capsid spike; P-type neutralization antigen, hemagglutination, cell attachment protein, involved in virulence; cleavage by trypsin into VP5 and VP8 enhances infectivity
5	NSP1	58.6	0	Nonstructural	Associates with cytoskeleton; extensive sequence diversity between strains; two conserved cystein-rich zinc finger motifs; RNA binding
6	VP6	44.8	780	Middle capsid	Major virion protein; middle capsid structural protein; homotrimeric structure; subgroup antigen; hydrophobic
7	NSP3	34.6	0	Nonstructural	Homodimer, specifically binds 3′ end of rotavirus mRNA; binds eIF4G1; involved in translational regulation
8	NSP2	36.7	0	Nonstructural	Nonspecific ssRNA binding; accumulates in viroplasm; involved in viroplasm formation; NT-Pase activity, homomultimer; binds NSP5 and VP1
9	VP7	37.4	780	Outer capsid	G-type neutralization antigen, N-linked high-mannose glycosylation and trimming
10	NSP4	20.2	0	Nonstructural	Enterotoxin, receptor for budding of DLP through ER membrane; N-linked high-mannose glycosylation; uncleaved signal sequence, rough ER transmembrane glycoprotein; modulates intracellular Ca2+
11	NSP5	21.7	0	Nonstructural	Interacts with NSP2 and NSP6; homomultimerizes; autocatalytic kinase activity; binds single-stranded RNA
	NSP6	12	0	Nonstructural	Product of second out of frame ORF; interacts with NSP5; localizes to viroplasm

Table adapted from Estes and Kapikian 2007, Feild's virology, 5th ed.