Disease relevance of K196R

• Expression and characterization of the thymidine kinase gene of African swine fever virus [1].
• The deduced amino acid sequence shows 32.4% identity with the TK of vaccinia virus [1].
• Identification of this region as the ASFV TK gene was confirmed by expression of TK in Escherichia coli and by the synthesis of active TK in a cell-free system programmed with RNA synthesized in vitro [1].
• The similarity scores obtained after comparison of known thymidine kinase sequences indicated that the African swine fever virus thymidine kinase is more distantly related than the poxvirus thymidine kinases to their cellular homologs [2].
• The Malawi TK deletion mutant showed reduced virulence for swine, producing transient fevers, lower viremia titers, and reduced mortality [3].

High impact information on K196R

• The African swine fever virus thymidine kinase gene is required for efficient replication in swine macrophages and for virulence in swine [3].
• Attempts to isolate double-crossover TK gene deletion mutants on swine macrophages failed, suggesting a growth deficiency of TK- ASFV on macrophages [3].
• Recombinant TK gene deletion viruses were produced by using two highly pathogenic isolates of ASFV through homologous recombination with an ASFV p72 promoter-beta-glucuronidase indicator cassette (p72GUS) flanked by ASFV sequences targeting the TK region [3].
• Two pathogenic ASFV isolates, ASFV Malawi and ASFV Haiti, partially adapted to Vero cells, were used successfully to construct TK deletion viruses on Vero cells [3].
• The TK gene was mapped within a 0.72-kbp BglII-XhoI fragment (0.242 to 0.246 map units) derived from a 23.9-kbp SalI-B fragment of the ASFV genome [1].

Biological context of K196R

• The thymidine kinase (TK) gene of African swine fever virus (ASFV) was located within the viral genome by using two degenerate oligonucleotide probes derived from sequences of the vaccinia virus and cellular TK genes [1].
• The sequenced gene for TK includes an open reading frame of 588 nucleotides encoding a protein of 196 amino acids [1].
• The thymidine kinase gene of African swine fever virus was mapped in a 1.4-kb EcoRI-PstI fragment located in the left half of the Eco RI K fragment of African swine fever virus DNA by using degenerate oligonucleotide probes derived from regions of the thymidine kinase sequence conserved in several poxviruses, man, mouse, and chicken [2].
• A general insertion/coexpression plasmid vector, pEPV2, has also been constructed. pEPV2 facilitates the insertion of foreign genes, together with the Lac Z reporter, into the thymidine kinase locus of ASFV [4].
• For the development of this neutralization assay 4 mutant viruses were generated by homologous recombination, containing beta-galactosidase or beta-glucuronidase reporter genes inserted into the thymidine kinase locus of the viral genome [5].

Analytical, diagnostic and therapeutic context of K196R

• The TK gene is not essential for growth of ASFV in cell culture and a stable viral strain deficient in TK has been isolated (E70NTKp) [6].

References