Using the larvae of the silkworm, Bombyx mori, we examined the baculovirus expression vector system for the expression of
the enhanced green fluorescence protein (EGFP) gene under the control of several gene promoters in vivo. To investigate the genedelivery
efficiency of the baculovirus into various larval tissues, we constructed two recombinant baculoviruses carrying the EGFP
gene downstream of the Drosophila melanogaster hsp70 gene promoter from B. mori nucleopolyhedrovirus (BmNPV) and Autographa
californica nucleopolyhedrovirus (AcNPV). After injection of these recombinant baculoviruses into newly ecdysed 5th instar
larvae, hsp70::EGFP-BmNPV, but not hsp70::EGFP-AcNPV, caused intense expression of EGFP not only in various non-neural
tissues, but also in the neural organs including the brain 5 days postinfection. To investigate the cell-specific expression in the
brain, we constructed recombinant C4/B3::EGFP-BmNPV and PTTH::EGFP-BmNPV which carry the EGFP gene under the control
of bombyxin B3 and prothoracicotropic hormone (PTTH) gene promoters, respectively. Injection of these recombinant baculoviruses
caused specific expression of EGFP with a high gene-expression efficiency in the neurosecretory cells of the brain depending on
the neurohormone gene promoters. Present results indicate that this in vivo gene-expression system mediated by the baculovirus
can serve as an efficient system permitting gene delivery into neural tissues in insects.
2002 Elsevier Science Ltd. All rights reserved.