Objective: To construct a fusion anti-caries DNA vaccine pGLUA-P carrying GLU fragment from gtfB gene of Streptococcus mutans GS-5 and A-P fragment including the A region and P region of PAc protein from a DNA anti-caries vaccine pCIA-P, and to investigate its expression in prokaryotic and eukaryotic cells.
Methods: The sequence of GLU fragment in pGLU plasmid was testified by DNA sequencing. The fusion anti-caries DNA vaccine was constructed by ligating A-P fragment from pCIA-P to pGLU. The expression of GLUA-P fusion protein in E. coli BL21 (DE3) was induced by IPTG and checked by SDS-PAGE electrophoresis. pGLUA-P was transfected in vitro to cultured rat primary muscle cells by cation liposome Dosper, and immunohistochemical method was used to test the expression of GLUA-P fusion protein in cells.
Results: GLU sequence was identical with relative sequence of GTF-I (GS-5 strain) in Gene Bank. Recombinant eukaryotic expression plasmid pGLUA-P was confirmed to have both GLU and A-P fragment. After pGLUA-P was transferred into E. coli (DE3), it could express a new 115 000 protein by the induce of IPTG. Specific brown products could be found in the cytoplasm of cultured rat primary muscle cells transfected by pGLUA-P.
Conclusions: Fusion anti-caries DNA vaccine pGLUA-P is successfully constructed and confirmed by sequencing and enzymes digestion. Fusion GLUA-P protein can be correctly expressed in prokaryotic and eukaryotic cells.