Sapelovirus A (SV-A) is a positive-sense single-stranded RNA virus which is associated with acute diarrhea, pneumonia and reproductive disorders. The virus capsid is composed of four proteins, and the functions of the structural proteins are unclear. In this study, we expressed SV-A structural protein VP1 and studied its antigenicity and immunogenicity. SDS-PAGE analysis revealed that the target gene was expressed at high levels at 0.6 mM concentration of IPTG for 24 h. The mouse polyclonal antibody against SV-A VP1 protein was produced and reached a high antiserum titer (1: 2,048,000). Immunized mice sera with the recombinant SV-A VP1 protein showed specific recognition of purified VP1 protein by western blot assay and could recognize native SV-A VP1 protein in PK-15 cells infected with SV-A by indirect immunofluorescence assay. The successfully purified recombinant protein was able to preserve its antigenic determinants and the generated mouse anti-SV-A VP1 antibodies could recognize native SV-A, which may have the potential to be used to detect SV-A infection in pigs.
Osteocalcin is a major non-collagenous component of the bone extracellular matrix and is considered to be an indicative factor of osteoblast differentiation. In the present study, we detected osteocalcin expression in different antler areas and growth phases by immunohisto- chemistry. Osteocalcin was highly expressed in all areas during the mineralization period and in mesenchymal cell and chondrocyte areas during the rapid growth period. The nucleotide sequence of the osteocalcin gene in sika deer antler was determined. The open reading frame was 303 bp encoding a protein of 100 amino acids. The estimated molecular mass of osteocalcin was 10.38 kDa and the theoretical isoelectric point was 5.37. The osteocalcin gene with a 6× His-tag at the C-terminus was cloned into the pGEX-4T1 vector and expressed in Escherichia coli under optimal conditions. The recombinant soluble protein fused with GST was purified with Ni-NTA resin. The purified osteocalcin protein exhibited a significant increase in HA adhesion and promoted antler chondrocyte proliferation. Osteocalcin is an important factor in regulating the rapid growth and differentiation of deer antlers.