The pSI Mammalian Expression Vector promotes constitutive expression of cloned DNA inserts in mammalian cells. The major difference between the pCI and pSI Mammalian Expression Vectors is the enhancer/promoter region controlling expression of the inserted gene. The pSI Expression Vector contains the simian virus 40 (SV40) enhancer and early promoter region. This vector can be used for both transient and stable expression of genes. For stable expression, the pSI Vector must be co-transfected with an expression vector containing a selectable gene for mammalian cells.|
Strong, Constitutive Expression: The pSI Vector's SV40 enhancer/promoter region allows strong, constitutive expression in most cell lines. The vector is maintained as an episome in cells expressing the SV40 large T antigen, leading to even higher levels of expression. A β-globin/IgG chimeric intron located downstream from the enhancer/promoter region can further increase expression. Increased Steady-State mRNA Levels: The late SV40 polyadenylation signal increases the steady-state level of RNA approximately fivefold more than the early SV40 polyadenylation signal.Convenient: Multiple cloning sites exist for easy insertion of cDNA. Versatile: Synthesize transcripts in vitro using the T7 RNA polymerase promoter or generate single-stranded DNA in E. coli using the f1 origin of replication.