baculovirussystemet

The baculovirus system refers to a group of insect-specific viruses that are widely used in molecular biology and biotechnology, particularly for protein expression. These viruses, belonging to the family Baculoviridae, are characterized by their large, double-stranded DNA genomes enclosed in rod-shaped nucleocapsids and occluded within a protein matrix called an occlusion body.

The most commonly employed baculoviruses for expression are derived from Autographa californica multiple nucleopolyhedrovirus (AcMNPV) and Bombyx mori nucleopolyhedrovirus (BmNPV). The system leverages the virus's natural ability to infect insect cells and replicate its genetic material, but the viral genome is engineered to carry a foreign gene of interest. This gene is typically placed under the control of a strong, insect-specific promoter, such as the polyhedrin promoter, which drives high-level expression of the foreign protein during the late stages of infection.

The baculovirus expression system offers several advantages, including the ability to express complex, eukaryotic proteins that may be difficult to produce in other systems, such as bacteria or yeast. It can perform post-translational modifications, such as glycosylation, which are crucial for the proper folding and function of many proteins. Furthermore, the high copy number of the viral genome within infected cells leads to very high protein yields.

The typical workflow involves cloning the gene of interest into a transfer vector, which is then co-transfected with linearized baculovirus DNA into insect cells. Recombinant baculoviruses that contain the foreign gene are then selected and amplified. These recombinant viruses are used to infect larger cultures of insect cells, where they efficiently produce the desired protein. The protein can then be harvested from the cells or the culture medium. The baculovirus system is particularly valuable for producing therapeutic proteins, diagnostic antigens, and research reagents.