OBJECTIVETo construct mouse Zinc-alpha2-glycoprotein (mZAG) eucaryotic expression plasmid and identify its expression in 3T3-L1 preadipocytes.

METHODSThe total RNA from mouse liver tissue was extracted. The reverse-transcript(RT)-PCR method was used to amplify the complete domain sequence of mZAG, and the confirmed PCR products was inserted into expression plasmid by DNA ligation. The mZAG expression plasmids with various concentrations (0, 0.4, 0.8, and 1.6 microg) were transfected into 3T3-L1 preadipocytes, and ZAG expression in mRNA and protein level was determined by real-time fluorescence quantitative PCR and Western blot, respectively.

RESULTSDNA sequencing confirmed the right sequence of mZAG expression plasmid pcDNA3.1(-)-mZAG. After the mZAG expression plasmid with different concentrations were transfected into 3T3-L1 preadipocytes, mZAG mRNA level significantly increased and reached 2.58 folds (P=0.002), 3.67 folds (P=0.000 and 5.19 folds (P=0.001) of that in the control group (no mZAG transfection). mZAG protein level also significantly increased and reached 2.75 folds of that in the control group (P=0.017). Treating 3T3-L1 cells with small interfering RNA (siRNA) sequence siRNA 1 and siRNA 4 resulted in a decrease of mZAG mRNA to 49% and 41% of those in the control group(no siRNA sequence transfection) (P=0.002P=0.000)and a decrease of mZAG protein to 55% and 62% of that in the control group (P=0.004,P=0.025).

CONCLUSIONSmZAG expression plasmid pcDNA3.1(-)-mZAG was successfully established in this study. This plasmid can be well expressed in 3T3-L1 preadipocytes. siRNA 1 and siRNA 4 can effectively inhibit the expression of mZAG in these cells.