ABSTRACT
<p><b>OBJECTIVE</b>To elucidate the potential molecular mechanism responsible for the early time of tumor promotion, gene expression profile was studied in the transformed BALB/c 3T3 cells induced by 12-O-tetradecanoylphorbol-13-acetate (TPA).</p><p><b>METHODS</b>The two-stage cell transformation model was established by using the initiator of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and promoter of TPA. Cell proliferation was measured by trypan blue staining and cell cycle analysis was carried out by flow cytometry assay. A cDNA microarray representing 1 152 genes was used to investigate the gene expression profiles of BALB/c 3T3 cells exposed to TPA at 4 h and 24 h respectively.</p><p><b>RESULTS</b>TPA could effectively inhibit cell proliferation and induce the G1 and S cell cycle arrested in the early time. Moreover 19 genes were found differentially expressed at least twofold in the TPA treated cells as compared with the control cells, 9 of them were upregulated and 10 downregulated. Most of the differentially expressed genes were involved in cell proliferation, differentiation or apoptosis, and related to ras or p53 signal transduction pathway.</p><p><b>CONCLUSION</b>TPA could influence the transcriptional expression of some genes related to cell cycle modulation and ultimately result in the cell growth arrest.</p>
Subject(s)
Animals , Mice , Apoptosis , Genetics , BALB 3T3 Cells , Cell Cycle , Genetics , Cell Differentiation , Genetics , Cell Proliferation , Cell Transformation, Neoplastic , Genetics , Flow Cytometry , Gene Expression , Gene Expression Profiling , Methylnitronitrosoguanidine , Pharmacology , Oligonucleotide Array Sequence Analysis , Methods , Tetradecanoylphorbol Acetate , PharmacologyABSTRACT
Phycoerythrocyanin(PEC) lyase-isomerase PecE/PecF from Mastigocladus laminosus is the specific enzyme for biosynthesis of PEC alpha-subunit(alpha-PEC). In this work, the specificity of PecE/PecF on substrate apoproteins was reported. PecE/PecF could catalyse the reconstitution of phycocyanobilin(PCB) with apoproteins of alpha-PEC from two different subspecies of Mastigocladus laminosus, as well the site-directed mutated apoprotein of alpha-PEC with Trp at 128 to Phe in vitro, but could not catalyse the reconstitution of PCB with apoprotein of phycocyanin alpha-subunit(alpha-CPC) from Mastigocladus laminosus. The surfactant Triton X-100 had no effect for the reconstitution of alpha-PEC, while it could improve the reconstitution of PCB with apoprotein of alpha-CPC.