AIM: To inhibit the expression of tyrosinase gene in murine B16 melanoma cells by antisense nucleotide. METHODS: The antisense recombinant pcDNA3.1(-)-tyr was constructed and was used to infect murine B16 melanoma cells for expression of tyr antisense nucleotide. The effect of antisense nucleotide of tyr on the expression of tyr gene was detected by determination of the activity of tyrosinase and of the production of melanin, Dopa staining and electronic microscope. RESULTS: The tyr antisense recombinant was successfully constructed and injected into murine B16 melanoma cell. The activity of tyrosinase in B16 cells infected with pcDNA3.1 (-)-tyr decreased to 0.0498?0.0036, compared to the tyrosinase activity of 0.0916?0.0132 in the control cells without treatment (P

AIM: The role of human interleukin-2(IL-2) signal peptide sequence in the effect of human Endostatin (hEndostatin) expression and secretion was investigated in HeG2 cells. METHODS: RT-PCR and Western-blotting were conduct to observe mRNA level difference of hEndostatin gene, its protein expression and secretion level difference between with hIL-2 signal peptide sequence and without it. RESULTS: mRNA level of hEndostatin gene in HepG2 (pBlast-hIL2-hEndo) cells was higher than that in HepG2(pBlast-hEndo)( P

AIM: Open reading frame(ORF) of death associa ted protein kinase1(DAPK1) gene was cloned for studying on tumor forming and met astasis.METHODS: Based on nucleotide sequence of DAPK1 gene f rom GenBank, a pair of primers was designed. DAPK1 gene ORF was transfected into Raji cells in expression vector pcDNA3.1(+) with lipofectamine reagent. Morphol ogic assessment of apoptosis was performed with fluorescence microscope cytotoxi city and cell viability was assayed by MTT. RESULTS: DAPK1 gene ORF was amprified from K562 cells by RT-PCR. It was cloned into plasmid pMD18-T and sequenced. There were seven mutation in 4 300 bp nucleotide sequence rel ativel y to DAPK1 nucleotide sequence from GenBank, but six was synonymous mutation and one was single nucleotide polymorphism. 4 300 bp nucleotide of DAPK1 gene O RF was transfected into Raji cells. DAPK1 gene expression was detected in 48 h a fter it was transfected into Raji cells. Then Raji cells showed apoptosis.CONCLUS ION: Large fragment gene was cloned by RT-PCR and transfected into Raji cells successfully. Over-expression of DAPK1 gene induced Raji cells apoptosis.

AIM: To construct pVAX1-GrB. METHODS: Lymphocytes from human laryngeal carcinoma tissue were separated from tumor tissue. The fragment of granzyme B (GrB) was amplified by RT-PCR and was recombined to the downstream of T7 promoter in the vector pVAX1. The construction was transfected into Hep2 cells with lipofectamine 2000. The expression of protein was identified by indirect immunofluorescent antibody assay. RESULTS: It has been proved that the sequence of the RT-PCR product was totally consistent with the data of GenBank by DNA sequencing analysis. The GrB cDNA fragment was cloned into the vector of pVAX1 in the right direction and the open reading fragment of GrB was maintained. The target protein was detected in the transfected Hep2 cells. CONCLUSION: The pVAX1-GrB plasmid was successfully constructed and expressed. [