The beta-galactosidase (lacZ) gene can be used reliably as a marker to detect and monitor baculovirus recombinants.
The juvenile hormone esterase (JHE) gene can be reliably used to estimate levels of foreign gene expression in insect cell culture and insect larvae. In some viruses it enhances the insecticidal activity of the baculovirus by reducing the weight gain in the feeding larvae. The host range of the recombinants remained unaltered.
A variety of transfer vectors (for polyhedrin and p10 replacement) were constructed to mediate and facilitate the introduction and detection of foreign genes into baculovirus recombinants. These vectors have been freely distributed to other research groups in Europe and the World. Deletion mutants (p10-minus, polyhedral envelope-minus) have been constructed and should result in reduced persistence of recombinants in the field. These mutants enhance the biosafety of genetically engineered baculoviruses, eg, provided with an insecticidal gene, as they reduce the risk for survival of recombinants in the environment.
A cDNA bank has been constructed from RNA isolated from the brain of fifth instar larvae of Spodoptera exigua as a source of insect hormone genes to be introduced into baculoviruses.