1Rev reverse primer (5′-GGGCGGCCGCCTACACTTGCAGTACTTGGCG-3′), which anneals to the 3′-end sequence of MS2/28.1. Escherichia coli expression of distinct
regions of the MS2/28.1 and purification of their products The coding sequences corresponding to amino acids 1 to 324 (the N-terminal region, region A), 326-344 (region B, 19-amino acid stretch lying immediately upstream of the putative cleavage site), 354-460 (region C, the region immediately downstream of the cleavage site), and 546-604 (the C-terminal 60 residues, region D) of the full-length MS2/28.1-associated ORF (referred to as MS2/28.1) were amplified by PCR using the three primer pairs 2/28.1For (5′-GGGATCCATGAAAAATAAAAAAATTAAATT-3′)-TGA1R (5′-GCGGCCGCTTGAGCTGTTCATTGGAAT-3′), TGA1F(5′-GGATCCATTCCAATGAACAGCTCAA-3′)-TGA2R learn more (5′-GCGGCCGCAGCTTTGGCTCAAGCTCTA-3′), and TGA6F (5′-GGATTCATATACTTGAAAAAATCCA-3′)-2/28.1Rev PXD101 (5′-GCGGCCGCCTACACTTGCAGTACTTGGCG-3′) and cloned into BamHI/NotI-restricted
pGEX-4T-1 expression vector, after being verified by nucleotide sequencing. The coding sequence of the region immediately downstream of the cleavage site (354-460, region C) was obtained from a plasmid containing the MS2/28.1 segment and subcloned in the EcoRI site of pGEX-4T-1. The recombinant plasmids encoding regions A, B, C, and D of MS2/28.1 were electroporated into competent E. coli strain BL21, to produce the GST-MS2/28.1A, GST-MS2/28.1B, GST-MS2/28.1C, and GST-MS2/28.1D fusion proteins, respectively. Briefly, overnight cultures of transformed bacteria were diluted 1:100 of 2YT medium containing this website ampicillin (100 μg/ml) and grown at 37°C with shaking (250 rpm) to an A600 of 0.6. Protein expression was induced by the addition of 0.1 mM IPTG, and maintained for 4-h incubation at 30°C with vigourous agitation (250 rpm). The cells were then pelleted by centrifugation at 3000 rpm and resuspended in 1× PBS. The E. coli pellet was disrupted by sonication and solubilized with 1% Triton
X-100 (Sigma) of 30 min. Both fusion proteins proved to be soluble and were readily purified by affinity chromotography on Glutathione Sepharose 4B Beads (GE Haelthcare), using the Bulk GST Purification Module, following the instructions of the manufacturer. The purified recombinant proteins were analysed by electrophoresis on sodium dodecyl sulfate (SDS)-12% polyacrylamide gels and allowed to react, in western immunoblotting, with a rabbit polyclonal anti-M. synoviae serum. Production of monospecific antisera to MS2/28.1 regions A, B, C, and D Polyclonal monospecific antisera to the purified fusion proteins GST-MS2/28.1A, GST-MS2/28.1B, GST-MS2/28.1C, and GST-MS2/28.1D were raised in female New Zealand White rabbits.