Abstract: Objective TO research the protein-protein interaction between ribonuclease inhibitor(RI) a?nd angiogenin(ANG) mutant. Methods Construct pCMV-3×flag-ANGH13R and pCMV-3×flag-ANGH114R pl?asmid.Immunofluorescence assay and laser scanning confocal microscopy analysis were used to observe the co-localization between RI and ANG mutant in BIU-87 cells.The interaction between RI and ANG mutant in BIU-87 cells was identified by glutathione-S-transferase (GST) pull-down assay and co-immunoprecipitation assay. Results The expressing plasmid pCMV-3×flag-ANGH13Rand pCMV-3×flag-ANGH114Rwas verified by restriction enzyme digestion and DNA sequencing.We found that RI was coloc-alized with ANG mutant in BIU-87 cell by laser scanning confocal microscopy analysis.Prokaryotically expressed products were purified and their sequences were confirmed.Glutathione-S-transferase(GST) pull do?w?n and co-immunoprecipitation results showed that the interaction between RI and ANG mutant occur?r?ed in BIU-87 cells. Conclusion The interaction between RI and ANG occurs in BIU-87 cells. The difference between RI and ANG mutant exists in BIU-87 cells.

Key words: angiogenin mutant, ribonuclease inhibitor, BIU-87 cell, interaction