Abstract: Objective   To construct a GCV-ribozyme recombinant vectors of α-8 giardin in Giardia lamblia.  Methods   The secondary structure of α-8 giardin mRNA （GenBank Accession No. AY781323） was analyzed with the RNA draw software. According to the proportion of G ∶ C and principles of designing hammerhead ribozyme，suitable ribozyme cleavage points were chosen. A specific antisense-hammerhead ribozyme（H8）was designed and synthesized. The ribozyme was cloned into Giardia canis virus （GCV） vector to construct a recombinant viral vector-pGCV634/H8/1423. The vector was linearized and transcripted into the trophozoites of G. lamblia by electroporation method. The α-8 giardin mRNA level of the transfectants and normal trophozoites were analyzed 24 h after electroporation by RT-PCR.   Results   The recombinant vector of GCV-specific hammerhead ribozyme of α-8 giardin in Giardia lamblia（pGCV634/H8/1423） was constructed. RT-PCR assays showed the ribozyme （H8） mRNA can be detected 24 h after transfection and α-8 giardin mRNA was cleaved effectively by ribozyme （H8） introcellularly.   Conclusion   pGCV634/H8/1423 can transfect Giardia trophozoites and cleave mRNA of α-8 giardin intracellularly.

Key words: Giardia lamblia；Giardin；&alpha, -8 giardin；Hammerhead ribozyme；Giardia canis virus （GCV）