EXPRESSION OF A GENE THAT ENCODES PHEROMONE BIOSYNTHESIS ACTIVATING NEUROPEPTIDE IN THE CENTRAL-NERVOUS-SYSTEM OF CORN-EARWORM, HELICOVERPA-ZEA

Expression of the pheromone biosynthesis activating neuropeptide (Hez- PBAN) gene in the central nervous system of larval, pupal and adult He licoverpa zea was studied using Northern hybridization analyses, rever se-transcriptase-polymerase chain reaction (RT-PCR), in situ hybridiza tion histochemistry, and whole-mount immunocytochemistry. Northern hyb ridization experiments demonstrated the presence of a 0.8-Kb Hez-PBAN transcript in the subesophageal ganglion in adults, pupae and day 0-1 final instar larvae. In the subesophageal ganglion, Hez-PBAN mRNA was localized by in situ hybridization histochemistry to the mandibular, m axillary and labial cell clusters. Whole-mount immunocytochemical stud ies showed that these three cell clusters also possess PBAN-like immun oreactivity. Low levels of Hez-PBAN mRNA were revealed in other parts of the central nervous system, including the brain, thoracic ganglia a nd abdominal ganglia by RT-PCR. In day 0-1 final instar larvae, these low levels of Hez-PBAN mRNA were localized by in situ hybridization hi stochemistry to a pair of ventral midline neurons in each thoracic gan glion and some abdominal ganglia. PBAN-like immunoreactivity was also detected in these neurons. This study shows that in H. zea, the Hez-PB AN gene is expressed predominantly in the subesophageal ganglion, and at relatively low levels in other parts of the central nervous system. (C) 1998 Elsevier Science Ltd. All rights reserved.