title: Complete genome sequence of attenuated low-temperature Thiverval strain of classical swine fever virus.
abstract: The Thiverval vaccine strain of classical swine fever virus (CSFV) was derived from virulent Alfort strain through the serial passages in cells at 29-30 degrees C. In this study, we determined the complete genome sequence of this strain and found that its genome contains one open reading frame (ORF) that encodes a polyprotein with 3,898 amino acids. The 5'-UTR of Thiverval is 373 nt long with only one mutation at position 220. In contrast, the length of 3'-UTR is highly heterogeneous ranging from 233 to 259 bp. The heterogeneity of length of the 3'-UTR was due to an insertion of a variable length of T-rich sequence ranging from 6 to 32 nt. The insertion may change the structure and free energy of the 3'-UTR, resulting in a destabilization of the 3'-UTR. Sequence alignment of Thiverval and other CSFV strains showed 85.2-99.6% identities at the nucleotide level and 92.5-99.5% at the amino acid level. The phylogenetic tree analysis of the complete ORF, partial region of E2, and NS5B suggests that the CSFV Thiverval strain belongs to genetic group 1 and subgroup 1.1. The results from this study provide insight into the molecular mechanism of the attenuation of Thiverval vaccine strain.
authors.affiliation: National Animal TSE Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, 100094 P.R. China.
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Fan
authors.forename: Qizu
authors.initials: Q
authors.lastname: Zhao
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhao
authors.forename: Qin
authors.initials: Q
authors.lastname: Wang
authors.forename: Yibao
authors.initials: Y
authors.lastname: Ning
authors.forename: Zhongqiu
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D020413:3' Untranslated Regions / Q000737:chemistry / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D006691:Classical Swine Fever / Q000821:virology*; D006692:Classical Swine Fever Virus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics; D016679:Genome, Viral; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010802:Phylogeny; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D013552:Swine; D013696:Temperature; D014765:Viral Vaccines / Q000235:genetics; D014774:Virulence
chemical_list: D020413:3' Untranslated Regions; D004279:DNA, Viral; D014765:Viral Vaccines