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Previously, VpPR-10.1 was isolated and characterized from a cDNA library of a fungus-resistant accession of Chinese wild grape (Vitis pseudoreticulata). We found that expression of VpPR-10.1 is affected by the fungal pathogen Erysiphe necator. To investigate the biochemical basis of the nuclease activity of VpPR-10.1 and its role in antifungal resistance, we generated recombinant VpPR-10.1 as well as site-directed mutations targeting three conserved amino acid residues among plant PR-10 s: Lys55, Glu149, and Tyr151. We showed that wild-type recombinant VpPR-10.1 exhibits both RNase and DNase activities. Mutant VpPR10.1-Y151H essentially retained all these activities. In contrast, VpPR10.1-K55N, where Lys55 in the P-loop region is mutated to Asn, and VpPR10.1-E149G, where Glu149 is mutated to Gly, lost their nuclease activity, indicating that both residues play a critical role in catalyzing RNA and DNA degradation. Furthermore, VpPR10.1 and VpPR10.1-Y151H inhibited the growth of the cultured fungal pathogen Alternaria alternate. Through transient expression in grapevine, we also demonstrated that VpPR10.1-K55N and VpPR10.1-E149G compromised resistance to E. necator. Finally, we further found that VpPR-10.1 can lead to programmed cell death and DNA degradation when incubated with tobacco BY-2 suspension cells. We show here that Lys55 and Glu149, but not Tyr151, are required for the RNase, DNase and antifungal activities of VpPR-10.1. The strong correlation between the level of VpPR-10.1 nuclease activity and its antifungal property indicates that the former is the biochemical basis for the latter. Taken together, our experiments revealed that VpPR-10.1 is critical in mediating fungal resistance in grape, potentially playing a dual role by degrading pathogen RNA and inducing programmed death of host cells. [ABSTRACT FROM AUTHOR]

The aim of this project was to investigate the anti-tumor effect of an IL-12 gene modified mammary sarcoma murine cell line, EMT6/IL-12, in mouse model. In this study, we transfected the recombinant eukaryotic plasmid encoding IL-12 gene (pcDNA6-p70) into EMT6 and obtained the IL-12 expressing EMT6/IL-12 cell line. Then EMT6/IL-12 cells were s.c. inoculated into mice. The recombinant vector treatment group was set as control. We then evaluated the inhibition of tumor growth and the anti-tumor immunity function in vivo such as cytotoxicity, proliferation of splenocytes and serial IFN-gamma level. And the percentage of IFN-gamma producing CD4 or CD8 T cells among splenocytes was also analyzed in tumor bearing mice. Our results showed that the growth of tumors was obviously inhibited in EMT6/IL-12 group. Moreover, the capacities of anti-tumor immunity were all significantly higher in EMT6/IL-12 group compared to the controls. The results of the present investigation support the notion that EMT6/IL-12 could exert gene therapy in tumor model by improving the anti-tumor cellular immunity.