(31)Acknowledgments The author thanks four anonymous referees Perifosine NSC639966 for their careful corrections to and valuable comments on the original version of this paper. This work was partially supported by the Foundation of the Research Program of Science and Technology at Universities of Inner Mongolia Autonomous Region under Grant no. NJZY13159, China.
Group A rotaviruses (GARV) are the major causes of viral diarrhea in a variety of animal young species worldwide [1]. In pig farms, they are responsible for economic losses due to death of animals, poor growth performance, and costs of diagnostic and treatment [2, 3]. Porcine GARVs are associated with weaning and postweaning enteritis in piglets and more often detected in piglets between 1 and 8 weeks of age [4, 5].

Rotavirus belongs to the family Reoviridae, subfamily Sedoreovirinae, and its genome consists of 11 segments of double-stranded RNA (dsRNA), which encode six structural proteins (VP1, VP2, VP3, VP4, VP6, and VP7) and six nonstructural proteins (NSP1�CNSP6), with all genes being monocistronic except for segment 11 which encodes two proteins, NSP5 and NSP6 [6]. Encoded by segment 8 (1059bp), NSP2 is a 35kDa protein which assembles into octamers and is composed of 317 amino acids [7]. NSP2 has a role in packaging and replication, performing activities of nonspecific binding to single-stranded RNA (ssRNA) to start the synthesis of dsRNA, translocation of viral RNA during packaging, and helicase ATP-independent, triphosphatase, and NDP kinase activities [7�C10].

NSP5 encoded by segment 11 (667bp) is a 21kDa protein that is hyperphosphorylated and O-glycosylated, and it consists of 198 amino acids, with abundance of serine (21%) and threonine (4.5%) [11�C13]. NSP5 interacts with NSP2 to form cytoplasmic structures known as viroplasms, inside of which RNA replication and morphogenesis of new viral particles occur [1, 14, 15]. The interaction Brefeldin_A with NSP2 also enhances the process of NSP5 hyperphosphorylation [9, 16]. The segment 11 also contains the coding sequence of NSP6 in a second ORF, whose function is still unknown, but it preliminarily interacts with NSP5 in dimerization and hyperphosphorylation processes. However, given the low levels of expression of NSP6, this suggests that this protein did not have an essential regulatory role [17�C19]. Traditionally, GARVs are classified on the basis of two outer capsid proteins (VP4 and VP7), which induce the formation of neutralizing antibodies, with the VP7 determining the genotype G, whereas VP4 determines P genotype [1, 6].