Separation, Characterization and Sexual Heterogeneity of Multiple Putative Odorant-binding Proteins in the Honeybee Apis mellifera L. (Hymenoptera: Apidea)

Abstract

According to precise molar mass determined by mass spectrometry and N-terminal sequence, some 25 odorant-binding-like proteins were characterized from the antennae and legs of worker and drone honeybees. Antennal specific proteins, composed of six different molecules, were classified into three subclasses according to N-terminal sequence homology. The major sexual difference was shown to lie in the relative abundance of these antennal specific proteins and in the occurrence of a drone-specific isoform. At least 19 other related proteins were found to occur in antennae and legs, forming another class showing homology with insect OBP. Genotype comparison of two honeybee races revealed a variability limited to this second class. Provided that these odorant-binding-like proteins are indeed able to bind odorants or pheromones, the question of whether their peculiar multiplicity contributes to the remarkable capacity of the honeybee to discriminate among a wide range of odor molecules is raised.

Cloning and Expression of a Queen Pheromone-Binding Protein in the Honeybee: an Olfactory-Specific, Developmentally Regulated Protein

“…The comparison with the native protein indicates that the 25-residue N-terminal sequence is cleaved after translation. The molar average mass 13,180.8 Da, calculated for the mature protein and assuming the formation of three disulfide bridges, was in perfect agreement with the measured molar mass (13,180.2 Ϯ 1.6 Da) of the native protein (Danty et al, 1998). Southern blot hybridization on genomic DNA raised only one band, suggesting that ASP1a and ASP1b are encoded by a single identical gene (data not shown).…”

“…was deduced from the peptide PEV F DLVA selected in the ASP1 N-terminal sequence (Danty et al, 1998). It was used for rapid amplification of cDNA ends (R ACE) 3Ј-specific amplification, and the 3Ј primer was 5ЈGAGAGAAC TAGC TCGAGTT.…”

“…Antennal protein extracts were prepared as described previously (Danty et al, 1998). Protein analysis was performed by nondenaturing electrophoresis adapted from Laemmli (1970) in a 16.8% acrylamide gel and separated in 2.5 hr at 250 V. Proteins were stained with a colloidal Coomassie blue-R (Serva Feinbiochemica, Heidelberg, Germany) 0.035% solution in 12% trichloroacetic acid and 5% ethanol and destained in water.…”

“…Search of honeybee OBPs was initiated a few years ago, leading to identification of three subclasses of antennal-specific proteins (ASPs), namely ASP1, ASP2, and ASP3 (Danty et al, 1997(Danty et al, , 1998. Based on sequence similarity and tissue specificity, ASP2 was assigned to be a member of the insect OBP family and the ASP3 subclass to belong to another family of olfactory proteins (McKenna et al, 1994;Pikielny et al, 1994;Maleszka and Stange, 1997).…”

“…Based on sequence similarity and tissue specificity, ASP2 was assigned to be a member of the insect OBP family and the ASP3 subclass to belong to another family of olfactory proteins (McKenna et al, 1994;Pikielny et al, 1994;Maleszka and Stange, 1997). Because of probable association of gOBPs and PBPs with neurons sensitive to general odors and to sex pheromone, respectively, ASP1 has been proposed to be associated with queen pheromone detection because of its higher abundance in drone, inverse to ASP2, supposed to interact with other odorants (Danty et al, 1998).…”