Abstract: Objective To explore the relationship between the expression of tau and DJ-i gene in transfected NIH3T3 cell by pEGFP-DJ-1 and pEGFP-DJ-iL166Pplasmid, and it would provide experimental basis to establish DJ-1 and DJ-iL166P transgenic mice and to understand the function of DJ-1 and the pathogenesis of Parkinson’s disease. Methods DJ-1 cDNA sequence were obtained from total RNAof SH-SY5Y cells by RT-PCR. Then one clone of the cDNA was treated with a mutation kit to get a mutation at the site which encodes the 166th amino acids. Recombinant pEGFP-ZV-i and pEGFP-DJ-i^L166P plasmids were constructed in a routine way. NIH3T3 cells were transfected into pEGFP-ZV-i，pEGFP-DJ-I^L166P, or pEGFP-C3 plasmids, and then the cells were selected with G418. The successfully transfected cells were analyzed by RT-PCR and Western blot to detect the expression of tau gene. Results We gained 6，2, and 9 clones of pEGFP-DJ-i, pEGFP-DJ-I^L166P, and pEGFP-C3 transfected cells. The results of RT-PCR and Western blot show that: the expression of tau in pEGFP-DJ-i transfected cells is lower than in pEGFP-C3 transfected cells, and the expression of tau in pEGFP-DJ-I^L166P, transfected cells is higher than in pEGFP-C3 transfected cells. The experimental result analyzed by statistics method is significant (P<0.05). Conclusion DJ-1 gene down-regulates the expression of tau on both transcription and translation levels, and DJ-I^L166P, up-regulats the expression of tau. The expression of tau is associated with DJ-i gene in NIH3T3 cell.

Key words: DJ-1, tau, Parkinson’s disease