Objective     To clone shRNA (short hairpin RNA) recombinant plasmid targeting on COX-2 gene and analyze the nucleic acid sequence of the recombinant plasmid.       Methods     One pair of 21 bp reverse repeated sequence targeting on COX-2 mRNA spaced by 9 bp nucleotides were synthesized. The complement double strands was formed by annealing and inserted into plasmid pGenesil-1 to generate eukaryotic expression plasmid. The recombinant plasmid was transformed into Jm109 strain

and the recombinant plasmid extracted was identified by restriction enzyme and sequence analysis. Inhibition effects of COX-2 mRNA and protein were detected by RT-PCR and Western blotting respectively.      Results     The target DNA was directly cloned to vector and the result was correct by sequence analysis. Compared to untransfected group

recombinant expression plasmid pshRNA-COX-2 resulted in reduction of COX-2 mRNA and protein expression to 69.9% and 50.3% respectively.      Conclusion     The recombinant plasmid targeting on COX-2 gene was successfully constructed

and it inhibited the expression of COX-2 gene significantly.