Biochemical analysis of proteins recognized by anti-HRP antibodies in Drosophila melanogaster: identification and characterization of neuron specific and male specific glycoproteins.

Antibodies recognizing horse radish peroxidase (HRP) stain neurons in Drosophila and other insects. We have used Western blots to analyze and characterize some of the anti-HRP reactive components from Drosophila melanogaster. Anti-HRP reactive components can be reproducibly detected during all developmental stages, although the pattern changes at different developmental times. In adults, there are at least 10 reproducibly stained components. Two of the bands, with molecular sizes of 42 and 80 kDa are likely to be the major contributors to neuronal anti-HRP staining in Drosophila. These components are enriched in adult fly heads. In contrast, many of the other anti-HRP reactive components in adults are enriched in abdomen and are present exclusively or at much higher levels in male flies. We have purified and characterized two of the male specific components with molecular sizes of 62 and 48 kDa. Partial N-terminal amino acid sequencing revealed that the 62 kDa protein is identical to a part of D. melanogaster carboxylesterase to EC 3.1.1.1) while he 48 kDa protein does not match any known sequences. Esterase-6 has previously been shown to be enriched in male accessory gland and consistent with this we show staining of this structure with anti-HRP antibodies.