Protein Expression|Proein Expression Introduction


Protein Expression
Protein expression has become a major tool to analyze intracellular processes, both in vitro and in vivo. The choice of expression system depends entirely on the purpose of the study. For some cases, transient transfection is the most obvious choice because of its relatively short time investment. In other cases, homogeneous populations and large quantities of cells may be required. This involves making cell lines that can stably express the desired protein. It may also be advantageous to express proteins under inducible promoters; this is particularly true if the protein exerts pathological effects on the cell. There are several inducible systems available but none, so far, is easy and straight-forward. Expression via viral infection is possible. Here, large quantities of cells can be infected at the same time and the protein assayed shortly after infection. The drawback of this technique, however, is the need for special precautions when making and handling virus stocks and the side-effects likely to be exerted by the virus on the cellular machinery. Protein expression can also be achieved directly via microinjection of plasmid DNA directly into the nucleus of the host call. This allows for protein expression in single cells, which may be desirable when performing video microscopy. Thus, the choices of expression systems are several and one should carefully consider the range of these available before investing time and other resources in the experiments themselves. Here, I introduce a life science research corporation, GenScript, which has shown both qulity and effciency in protein expression and purification projects.
Protein Expression Systems
	Bacterial Expression System	GenScript’s comprehensive service package starts with cloning the gene of interest and continues through a competitive four-week time frame to the delivery of milligram-levels of purified recombinant protein.
	Yeast Expression System	GenScript employs a transgenic yeast strain to glycosylate recombinant proteins in the same manner as mammalian cells, making it practical to produce proteins with increased applicability in human therapies. This yeast expression system also provides a creative and reliable approach to the expression of proteins that are difficult or impossible to express in other systems.
	Baculovirus Expression System	The baculovirus expression vector system (BEVS) is an eukaryotic system that facilities many of the post-translational protein modifications, processing, and transport systems present in high eukaryotic cells. GenScript’s baculovirus expression service package includes both virus production and large-scale protein production, suitable for the pharmaceutical and biotechnology industries and academic institutions. It has pioneered methods for the secretion of recombinant proteins from baculovirus-infected insect cells. They can produce milligram amounts of recombinant protein, suitable for functional screening and biological testing using either the customer's or our own purification processes. Their flexible services have considerable scale-up capacity.
	Mammalian Cell Expression System	GenScript recommends its mammalian expression service for cases in which the folding of the proteins is crucial to the customer's intended application and cases in which the internal machinery of E. coli is unable to express the protein in sufficient time or quality.
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Protein Expression

Protein Expression Systems