Bluetongue virus-17 fusion protein ns1 expressed in Escherichia coli by pUC vectors

Expression of the non-structural protein NS1 of bluetongue virus in bacteria and yeast: identification of two antigenic sites at the amino terminus

cDNA transcribed from bluetongue virus serotype 1 (Australia) dsRNA 5 coding for non-structural protein NS1 was amplified in a polymerase chain reaction and ligated downstream of the T7 RNA polymerase promoter in the bacterial expression plasmid pET-5b, as a fusion protein with glutathione S-transferase using the pGEX bacterial expression system or the metallothionein promoter in the yeast expression plasmid pYELC5. The linear epitopes bound by six monoclonal antibodies to NS1 were localised to two antigenic regions at the amino terminus by Western blots using a series of carboxy-terminal truncations of the NS1 protein overexpressed in Escherichia coli. Expression of truncated NS1 genes using the pGEX expression system in E. coli enabled a more detailed map of the two epitopes to be constructed. The first epitope is thought to lie between amino acid residues 40-59, while the second is defined by the peptide sequences flanking amino acid 96.

Expression of a full-length nonstructural protein NS1 of bluetongue virus serotype 17 in Escherichia coli

The relative abundance of the nonstructural protein NS1 in bluetongue virus (BTV)-infected cells, the existence of NS1 in the BTV particles and the highly conserved NS1 gene among BTV serotypes indicate the diagnostic potential of using NS1 in detecting BTV infections. In this study a NS1 gene was expressed with the T7 RNA polymerase expression system to produce a full-length NS1 protein. Sheep anti-NS1 antibodies were raised with the E. coli-produced NS1 and used to show that the NS1 proteins of the five BTV serotypes in the Unites States were immunologically indistinguishable.

Expression of bluetongue virus serotype 17 NS1 protein from a cloned gene

A full-length copy of the coding region of segment 6 from bluetongue virus (BTV) serotype 17 was constructed from five overlapping cDNA clones. The gene coding for the NS1 protein was cloned into an expression plasmid under the control of a bacteriophage T7 promoter and expressed both in vitro and in Escherichia coli BL21(DE3) cells which contain a T7 RNA polymerase gene in their chromosome. Expression in both systems resulted in the synthesis of a protein comigrating with NS1 and a minor polypeptide comigrating with another viral-induced protein, NS1a, sometimes seen in BTV-infected cells. The proteins induced in E. coli were synthesized to high levels as insoluble products.