Objective To construct the recombinant plasmid carrying the gene encoding Borna disease virus(BDV) phosphoprotein(p24),express in prokaryotic cells and purify the expressed product.Methods The p24 gene was amplified by RT-PCR from oligodendrocytes(OL) infected with BDV and cloned into prokaryotic expression vector pET-41a(+).The constructed recombinant plasmid pET-41a-p24 was transformed to E.coli BL21(DE3) for expression under induction of IPTG.The expressed protein was purified by affinity chromatography....