The regulation of foreign gene expression in Insect-Baculovirus Expression System is very complex. In this report, the effect of 5′-UTR in the expression of hGH gene in cultured Sf9 cells was examined. A 18 bp length in the end of 5′-UTR of hGH (human Growth Hormone, hGH) cDNA including a stem-loop structure was deleted by PCR. The truncated hGH cDNA, Δ1hGH was cloned in pFastBac1, named pFast-Bac-Δ1hGH. After transforming into E.coli. DH10Bac, which have a shuttle vetor-Bacmid, the Δ1hGH was integrated into Bacmid by site-specific transposition, and an expression vector, rBacmid-Δ1hGH DNA was acquired. By transfecting the cultured Sf9 cells with the recombinant expression vector DNA, pure recombinant virus, rAcV-Bac-Δ1hGH was obtained, and hGH gene was expressed. Immuno-blot and Chemiluminescent assay revealed that the expressed hGH had normal immunological activity, the ammount of hGH expression level in Sf9 cell supernatant infected with rAcV-Bac-Δ1hGH containing the truncated 5′UTR was four to five times higher than that infected with rAcV-Bac-hGH.
