Using Insect Cells For Making Mammalian Proteins

Recombinant protein expression is a major part of biological research. In theory, once the genetic code of a protein is known from cDNA analysis or whole genome sequencing, any polypeptide of interest, existing in nature or perceived, can be artificially produced. Bacteria cells are commonly used to express a variety of proteins because they are more convenient and less costly than other systems. However, a significant percentage of proteins naturally expressed in mammalian cells are not soluble or cannot be easily produced in bacteria such as E. coli. Like bacteria, yeasts are also easy to culture and manipulate, however, although they are eukaryotes, they are not capable of adding “mammalian-like” post-translation modifications (PTM). Insect cells can be used effectively for producing large quantities of mammalian proteins rather easily through baculovirus such as Allele´s Sapphire system. PTM in insect cells is not exactly the same as in mammalian cells, e.g. different glycosylation patterns, but is a lot closer than yeasts. Mammalian cells are used for proteins that require appropriate PTM or are not soluble in other systems through either transient transfection or stable cell line establishment.

For protein expression in insect cells, a number of factors need to be taken into consideration:

1) Genomic DNA for creating baculovirus stocks that will ensure a high percentage of recombinant virus (to avoid wild-type, non-producing virus)
2) Transfer plasmid for cloning the protein-encoding cDNA for easy cloning and appropriate co-expression of helper or marker proteins (such as through insect IRES)
3) Cell lines that have the highest expression levels of a particular protein, sometimes a number of cell lines need to be screened
4) Cell medium, because insect cell medium may contain high levels of ions that can interfere with affinity tag-based purification, one needs to find the most appropriate medium for protein expression
5) Secreted vs nonsecreted proteins. Insect cells need to have their own secretion signal (and translation signal, IRES, polyadinylation, etc.)

More reading…http://www.allelebiotech.com/protein-expression-in-insect-cells/

Tags: baculovirus, BVES, insect cells, insoluble proteins, mammalian proteins, protein expression, PTM, sf21, sf9, T. ni

Opportunities for business with Allele Biotech

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1) A novel method of discriminating and/or detecting mismatched polynucleotide populations in a sample, or determining the relative abundance of the species contained in the sample based on the changes in the relative ratios following a critical treatment. This technology, subject of a current patent application, can provide great benefits in polynucleotide-based diagnosis.

2) A technology on how to utilize the light-absorbing capabilities of certain light-absorbing proteins against damaging lights, or in cosmetic or beauty products. It is also a subject of a filed full patent.

3) Products that relate to detecting swine flu with novel antibodies of high specificity and stability. The antibodies have been tested in academic molecular biology labs in ELISA and strip formats.

4) Nanotechnology products that can be immediately applied to prevent citrus diseases on farms.

5) Enzymes as additives to animal feeds that help farm animals digest. The product is already being sold in certain regions.

Tags: beauty products, chicken feed, cosmetic, diagnosis, farm animals, skin care, swine flu