Chimerism

Figure 17.14 Model of evolved mutant from cephalosphorinase shuffling. The sequence of the most active cephalosporinase mutant was modeled using the crystal structure of the class C cephalosporinase from Enterobacter cloacae. The mutant and wild-type proteins were 63% identical. This chimeric protein contained portions from three of the starting genes, including Enterobacter (blue), Klebsiella (yellow), and Citrobacter (green), as well as 33 point mutations (red). (Courtesy of A. Crameri.)...

Chapter 13 Recombinant DNA Cloning and Creation of Chimeric Genes... 

FIGURE 13.2 Foreign DNA sequences can be inserted into plasmid vectors by opening the circnlar plasmid with a restriction endonnclease. The ends of the linearized plasmid DNA are then joined with the ends of a foreign sequence, reclosing the circle to create a chimeric plasmid. 

Seal gaps in chimeric plasmid widi DNA ligase... 

The first biologically functional chimeric DNA molecules constructed in vitro were assembled from parts of different plasmids in 1973 by Stanley Cohen, Annie Chang, Herbert Boyer, and Robert Helling. These plasmids were used to transform recipient E. coli cells transformation means the uptake and repli-... 

Cohen, S. N., Chang, A. C. Y, Boyer, H. W., and Helling, R. B., 1973. Construction of biologically functional bacterial plasmids in vitro. Proceedings of the National Academy of Sciences U.S.A. 70 3240 — 3244. The classic paper on the construction of chimeric plasmids. 

Cagnon, L., and Rossi, J. J. (2000). Down regulation of the CCRS beta-chemokine receptor and inhibition of HIV-1 infection by stable VAl-ribozyme chimeric transcripts. Antisen. Nuc. A. Drug Dev. 10 251—261. 

Maeda, Y., et al. (1997). Engineering of functional chimeric protein G-Vargula luciferase. Anal. Biochem. 249 147-152. 

Rizzuto, R., Marisa, B., Pizzo, P., Murgia, M., and Pozzan, T. (1995). Chimeric green fluorescent protein as a tool for visualizing subcellular organelles in living cells. Curr. Biol. 5 635-642. 

Recombinant soluble TNF-RI-IgGl fusion protein Etanercept, Enbrel is a chimeric molecule consisting of the extracellular domain of the TNF receptor I (TNF-RI) and the Fc portion of human IgGl. Two Fc domains are bound to each other via disulfide bonds, thereby yielding dimers with two binding sites for the TNF trimer. Etanercept binds with high affinity to extracellular TNF and reduces TNF activity. Etanercept is not effective in Crohn s disease, possibly because it does not lead to destiuction of membrane TNF-a expressing cells. Indications and side effects are similar to those of Infliximab and Adalimumab. 

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