Baculovirus and Expression Vector System for Insect Cells

Baculovirus and Expression Vector System for Insect Cells - Development of baculovirus expression vector system is based on its life cycle which involves the following steps:

(i)in early phase (12 hours), virus particles are budded from infected cells and spread the virus;

(ii)In the late phase (2-5 days), occluded virus units accumulate in the nucleus and get embedded in protein polyhedra

(iii)Insect is decomposed releasing polyhedra

(iv) polyhedra are ingested by another insect, where polyhedra are dissolved releasing virus for multiplication

The use of baculovirus as a cloning and expression vector involves following steps

(i) desired gene is cloned in a transfer vector under the control of polyhedrin promoter

(ii) chimeric transfer vector is contransfected with wild type virus into the host cell;

(iii) polyhedrin gene of wild type is replaced by cloned gene through recombination

(iv)Recombinant virus is plaque purified, since they will have no polyhedra occlusion bodies

(v)The selected recombinant virus is multiplied and used for expression of heterologous protein