›› 2012, Vol. 55 ›› Issue (11): 1246-1254.doi:

• RESEARCH PAPERS • Previous Articles     Next Articles

Cloning, expression and subcellular localization of the olfactory co-receptor Orco gene in the Chinese honeybee, Apis cerana cerana (Hymentoptera: Apidae)

ZHANG Lin-Ya, XIE Bing-Hua, NI Cui-Xia, ZHAO Lei, LI Hong-Liang, SHANG Han-Wu   

  • Received:2012-10-18 Revised:2011-11-18 Online:2012-11-20 Published:2012-11-20
  • Contact: LI Hong-Liang E-mail:hlli@cjlu.edu.cn
  • About author:zoezhanglinya@yahoo.cn

Abstract: 【Aim】 To clone and identify the olfactory receptor co-receptor (Orco) gene in the Chinese honeybee, Apis cerana cerana, and locate its proteins in the worker’s antennae. 【Methods】 The olfactory receptor Orco gene from honeybee A. cerana cerana was cloned by RT-PCR, and the expression of this gene at different developmental stages and in different tissues of the honeybee were profiled by Real-time PCR. The putative amino acid sequence was analyzed by bioinformatics methods, and the sub-cellular localization of Orco in the worker’s antennae was detected by immunofluorescence. 【Results】 The full-length cDNA sequence of olfactory receptor Orco was obtained from A. cerana cerana, and named as AcerOrco (GenBank accession no. JF968610.1). Its open reading frame is 1 434 bp in length, encoding 477 amino acid residues. Homology analysis showed that the amino acid sequences of AcerOrco contain seven-transmembrane domains and four hydrophilic regions outside the membrane. The expression profiling at different developmental stages showed that AcerOrco was expressed in the egg, larval and pupal periods at very low levels. The expression profiling in different tissues revealed that AcerOrco was highly expressed in the antennae and legs in nurse bee, with the highest level in the antennae of the 1 day-old worker, while in forager it was highly expressed in antennae, head (without antennae), thorax, abdomen and wings. Subcellular localization displayed that AcerOrco was largely expressed in pairs in the antenna of forager, especially in the 1st flagellar segment of antenna. Furthermore AcerOrco was seemingly to be mainly expressed in the outer dendrite (OD) neurons of sensilla trihodea and the dendrites of sensilla placodea in antennae. 【Conclusion】 The full-length olfactory receptor gene AcerOrco and its expression profiles were obtained, and the encoded protein in the forager antenna of worker honeybee was successfully localized using immunofluorescence. It is inferred that AcerOrco is closely related with the olfactory development and functions of antennal sensilla in the honeybee.

Key words: Apis cerana cerana, olfactory receptor, expression profiling, antennal sensilla, immunofluorescence localization