Transfected cells

Another member of the FGF family, FGF-4, protects against radiation-iaduced ceU killing and enhanced the G2 arrest when overexpressed ia a human adrenal cortical carcinoma ceU line (196). This effect is again manifested as the appearance of a shoulder on the survival curve, although neither the control nor the transfected cells undergo radiation-iaduced apoptosis. No differences ia the yield or repair of either SSBs or DSBs have been observed. 

There are various protocols of administering eukaryotic expression vectors aiming to deliver (i.e. transfect) the DNA into the cytoplasm of the host cells (see Figure 2). The DNA is subsequently imported into the nucleus of the transfected cells allowing expression of the... 

Transfected cell systems with high expression levels Coupling to Gs, stimulation of cAMP production ... 

Transfect cells, add Inducing agent, then L break cells... 

Chimeric DNA molecules are introduced into cells to make transfected cells or into the fertilized oocyte to make transgenic animals. 

Fig. 3. Comparison of transfection efficiencies obtained using PolyFect Reagent, a dendrimer-based transfection reagent, and a calcium phosphate-mediated procedure. COS-7 and HeLa cells were transfected in srx-weU plates with a /3-galactosidase expression plasmid using the appropriate protocol. For the calcium phosphate-mediated transfection, 6 pg of plasmid DNA was used and the medium was changed after 5 h incubation. Transfections were performed in triplicate, and transfection efficiency was measured by monitoring the /3-galactosidase activity of extracts obtained from the transfected cells. The amoimt of /3-galactosidase activity in the extracts correlates with the transfection efficiency. Cells were harvested 48 h post-trans-fection...

Bennasser Y, Yeung ML, Jeang KT (2006) HIV-1 TAR RNA subverts RNA interference in transfected cells through sequestration of TAR RNA-binding protein, TRBP. J Biol Chem 281(38) 27674-27678... 

Expression studies in Xenopus oocytes or transfected cell lines originally suggested that functional GABA-activated chloride channels could be formed by receptor subunits of each class in isolation. However, much better expression occurs with two or more subunit types in combination and it is likely that most native receptors contain at least three different subunits. Co-expression of a and /I subunits results in the assembly of... 

Elroy-Stein, D., Bernstein, Y. and Groner, Y. (1986). Overproduction of human Cu/Zn-superoxide dismutase in transfected cells extenuation of paraquat-mediated cytotoxicity and enhancement of lipid peroxidation. EMBO J. 5, 615-622. 

The study of active transport mechanisms has grown substantially in recent years, with transport proteins such as P-gp, BCRP, and MRP-2 among the most studied [59]. Several types of in vitro assays to assess substrates of transporters have been established these include assays directed toward intestinal and biliary efflux [60]. Assays that measure passive and active transport are also used to assess penetration of the blood-brain barrier. In addition to the assays described above, transfected cell lines that overexpress transporters present in the blood-brain barrier are also employed [61]. 

Cui, Y., J. Konig, and D. Keppler. Vectorial transport by double-transfected cells expressing the human uptake transporter SLC21A8 and the apical export pump ABCC2, Mol. Pharmacol. 2001, 60, 934—943... 

It is also important to predict the in vivo biliary excretion clearance in humans, and for this purpose MDCK II cell lines expressing both uptake and efflux transporters may be used (Fig. 12.3) [92, 93]. It has been shown that MRP2 is expressed on the apical membrane, whereas OATP2 and 8 are expressed on the basolateral membrane after cDNA transfection (Fig. 12.3) [92, 93]. The transcellular transport across such double-transfected cells may correspond to the excretion of ligands from blood into bile across hepatocytes. Indeed, the vectorial transport from the basal to apical side was observed for pravastatin only in OATP2- and MRP2-expressing... 

---