title: The N-terminus of classical swine fever virus (CSFV) nonstructural protein 2 modulates viral genome RNA replication.
abstract: Pestivirus nonstructural protein 2 (NS2) is a multifunctional, hydrophobic protein with an important but poorly understood role in viral RNA replication and infectious virus production. In the present study, based on sequence analysis, we mutated several representative conserved residues within the N-terminus of NS2 of classical swine fever virus (CSFV) and investigated how these mutations affected viral RNA replication and infectious virus production. Our results demonstrated that the mutation of two aspartic acids, NS2/D60A or NS2/D60K and NS2/D78K, in the N-terminus of NS2 abolished infectious virus production and that the substitution of arginine for alanine at position 100 (NS2/R100A) resulted in significantly decreased viral titer. The serial passage of cells containing viral genomic RNA molecules generated the revertants NS2/A60D, NS2/K60D and NS2/K78D, leading to the recovery of infectious virus. In the context of the NS2/R100A mutant, the NS2/I90L mutation compensated for infectious virus production. The regulatory roles of the indicated amino acid residues were identified to occur at the viral RNA replication level. These results revealed a novel function for the NS2 N-terminus of CSFV in modulating viral RNA replication.
authors.affiliation: State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Li
authors.affiliation: State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
authors.forename: Fengwei
authors.initials: F
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China. Electronic address: zspan@whu.edu.cn.
authors.forename: Zishu
authors.initials: Z
authors.lastname: Pan
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D002460:Cell Line; D006692:Classical Swine Fever Virus / Q000235:genetics / Q000502:physiology*; D004252:DNA Mutational Analysis; D016297:Mutagenesis, Site-Directed; D012367:RNA, Viral / Q000096:biosynthesis*; D012692:Serial Passage; D013489:Suppression, Genetic; D013552:Swine; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication
chemical_list: D012367:RNA, Viral; D017361:Viral Nonstructural Proteins
keywords: Classical swine fever virus; Nonstructural protein 2; Replication; Replicon