RESUMO
Objective To construct several human proinsulin mutants plasmid related to diabetes and to express in INS-1 (Insulin secreting beta cell derived line) cell. Methods Human mild proinsulin gene was used as template , and site-directed mutagenesis PCR was employed to generate four human proinsulin plasmid mutants. Each mutant plasmid was sequenced then transfected with empty plasmid and mild plasmid into INS-1 cell by liposome 2000. Insulin value in each cell solution was determined by radioimmunoassay. Results Proinsulin mutants plasmid were confirmed by sequencing. In-sulin values in culture solution of H-C(B19)G、H-L(B11)P、H-R(S6)C mutants are less than those in wild type and H-F (B25)L(P＜0.05). Comparison of insulin values between H-C(B19)G、H-L(B11)P、H-R(S6)C groups were not statistically significant(P>0.05), and all these three groups showed no significant differences with empty plasmid group statistically (P>0.05).Insulin value of H-F(B25)L was of no significant differences statistically with empty plasmid(P>0.05). Conclu-sion Four human proinsulin mutants plasmid were constructed and expressed successfully in INS-1 cell, and different mu-tants plasmid result in diabetes through different mechanism.