Chem. Senses 27: 319-332,
2002
© Oxford University Press 2002
Novel Odorant-binding Proteins Expressed in the Taste Tissue of the Fly
Biological Institute, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
Correspondence to be sent to: Masayuki Koganezawa, Biological Institute, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan. e-mail: kogane{at}mail.cc.tohoku.ac.jp
A taste tissue cDNA library of the fleshfly Boettcherisca
peregrina was screened with a subtracted cDNA probe enriched with
taste-receptor-tissue-specific cDNA. Seven genes were identified with sequence
similarity to insect odorant-binding protein (OBP) genes. The predicted amino
acid sequences of the genes contain the putative signal peptide sequence at
the N-terminal and most of them conserve the six cysteines common to known
insect OBPs. These genes show a high degree of sequence divergence with
20% amino acid identity. The most striking feature was that all seven of
these genes are expressed mainly in the taste tissues, such as the labellum
and tarsus, unlike the known insect OBP genes expressed in olfactory tissue.
The predicted amino acid sequences had the highest degree of sequence
similarity to the Drosophila melanogaster OBPs named pheromone
binding protein-related proteins (PBPRPs). These gene products are here
referred to as gustatory PBP-related proteins (GPBPRPs) 1-7. Homologous GPBPRP
genes were found also in D. melanogaster by database search and are
shown to be expressed in Drosophila taste tissues.