subject: Insect Expression Systems [print this page] Insect Expression Systems Insect Expression Systems
Protein expression is a widely used application throughout biotechnology, medicine and the life sciences. Large quantities of protein and enzymes are used by molecular biologists and a lot of of these come from expression systems, for example, DNA polymerase is used in PCR, a widespread technique that is used to amplify specific strands of DNA so that there is sufficient DNA quantities to use in downstream applications like DNA sequencing or cloning.
All DNA contains coding sequences called genes, these genes include the information on how to make proteins that generate every structure in our bodies, so genes are effectively templates used to produce proteins. Protein expression exploits this naturally occurring process and amplifies proteins from genes to be used in biotech, medical and life science applications. There are a few different kinds of protein expression, however the most widespread are cell based systems that generally include a host cell containing an expression vector, the gene to be expressed is cloned into the expression vector, then the host cell is placed into conditions to amplify its growth, the cells are later harvested and the protein is purified from the cells.
Insect expression uses baculovirus based protein expression, baculoviruses are present in two main types, granuloviruses and nucleopolyhedroviruses. They do not replicate in mammalian cells, however they have over 600 host species in invertebrates, with larval moth species being the most common. They have been used for over 20 years now to generate proteins in insect cell cultures, these are recognized as recombinant proteins and have been used in research and as vaccines in both human and veterinary therapies, a good example is avian flu, it was treated using recombinant proteins produced using a baculovirus expression system. Proteins produced this way are at present being studied as therapeutic cancer treatments with several immunologic advantages over proteins manufactured from mammalian sources.
Insect expression offers numerous advantages over other host systems, including high yield, high activity, flexibility and ease of scale up. Insect cells are excellent for expression because they do not need C02 to grow and can be easily set up in high density cell cultures for large scale expression.
