Heterologous Expression System

A great number of systems are available for the expression of viral structural proteins and analysis of their assembly. These systems include both prokaryotic and eukaryotic environments and the products can be assembled either within the cells or in vitro, using cell lysates or purified components. Table I summarizes the systems that have been used for viral assembly and lists their key advantages and disadvantages. 

Summary of M yor Heterologous Expression Systems for the Assembly of Viruslike Particles 

Recombinant Moderate to high yield assembly baculovirus of VLPs ffequendy observed  

Recombinant Moderate yield assembly of vaccinia virus VLPs ffequendy observed  

Protein frequently insoluble may not assemble into particles parallel expression of multiple proteins difficult 

---

Heterologous expression systems comprise prokaryotic organisms (e.g., E. coli) and eukaryotic cells (e.g., yeast, HEK293, Xenopus oocytes), which are used to functionally express foreign genes or cDNAs. 

Heparin Sulfate Proteoglycans Hepatic Lipase Hepatitis Hepatitis C Heptahelical Domain Heptahelical Receptors HERG-channels Heterologous Desensitization Heterologous Expression System Heterotrimeric G-Proteins Hidden Markov Model High-density Lipoprotein (HDL)... 

Daniel, H., Nutrient transporter function studied in heterologous expression systems, Ann. N. Y. Acad. Sci. 2000, 915, 184-192. 

Subunits of the GluR5-GluR7 family, on the other hand, coassemble with KA1 or KA2 into functional kainate receptors when studied in heterologous expression systems. Results of experiments with radioligands demonstrate that homomeric GluR5 and GluR7 receptors... 

Heterologous expression systems hERG current (whole cell patch clamp) Mammalian cell expression (CHO, HEK-293, mouse L-ceUs, COS-7) and Xenopus oocytes expression system Witchel et al. 77 Zou et al. 78 Cavero et al. 79 Martin et al. 80 McDonald et al.81... 

The Advantages of Using Oocytes as a Heterologous Expression System that... 

Theodoulou FL, Miller AJ. 1995. Xenopus oocytes as a heterologous expression system. Methods Mol Biol 49 317. 

The Argl37His AVPR2 variant has been the subject of detailed study in heterologous expression systems (123). Vasopressin binds the variant with affinity similar to the wild type however, it fails to stimulate G a. This evidence suggests that the conservation of an arginine at this position is necessary for receptor-coupled G protein activity (115,123,124). 

Murine crjptochrome 1 shows light-dependent binding to PI A S in a heterologous expression system... 

With the advent of recombinant DNA technology, it is feasible to produce subcellular or subunit vaccines using heterologous expression systems, rather than partially purihed components from the native source... 

Human CYPlAl has been expressed in several of the heterologous expression systems including yeast, human lymphoblasts, V79 cells and human fibroblasts. The EROD activity in V79 cells expressing CYPlAl is 50pmol/(mg total protein x min) (Schmalix et al., 1993). In human lymphoblasts, EROD activity of 155 pmol/(mg microsomal protein X min) was obtained (Penman et al., 1994). EROD activity in human fibroblasts expressing CYPlAl cDNA is 1.2pmol/(10 cells x min) or approximately... 

---