Abstract: Odorant binding proteins (OBPs) in insects play an important role in foraging, courtshipping, multiplying and chemical communication with the environments. Antennalbinding protein (ABP) is one of important groups of OBP family. We analyzed the first reported ABP and ABPX genes in the silkworm Bombyx mori using chromosome mapping and semi-quantitative RT-PCR for further understanding of the expression and function of ABP/ABPX. Chromosome mapping showed that BmABP and BmABPX were respectively organized in chromosome 5 and 26 with different gene structure, suggesting that they probably possess different functions. Analysis of the expression profiles in different tissues of males and females during the embryonic, larval and adult stages revealed that BmABP possessed high expression level in a variety of tissues and organs with no time- and tissue-specificity, while BmABPX possessed conspicuous temporal and spatial expression differences (P<0.05), with the highest relative expression level in the antenna, and lower relative expression levels in most other non-olfactory tissues without significant sex differences. The results suggest that these two genes are more likely to have other functions undiscovered besides olfactory-related functions.

Key words: Bombyx mori, odorant binding protein (OBP), ABP gene, ABPX gene, expression analysis, chromosome mapping