家蚕信息素结合蛋白BmPBP2和BmPBP3基因的初步鉴定及表达分析

嗅觉对昆虫的生存、繁殖等起着重要的作用。依据家蚕Bombyx mori全基因组序列设计特异引物，扩增得到了两个信息素结合蛋白BmPBP2和BmPBP3基因的cDNA片段。结合已报道的家蚕信息素结合蛋白BmPBP1和两个普通气味结合蛋白BmGOBP的信息，对其基因结构分析表明，这5个基因均由3个外显子组成，具有保守的外显子/内含子边界和典型的6个Cys残基，且3个PBP基因在基因组上串联分布。序列同源性分析表明，BmPBP2和BmPBP3与烟草天蛾的PBP2和PBP3的同源性高达69%和63%。半定量RT-PCR分析结果显示，BmPBP2和BmPBP3基因在成虫触角中特异表达，且雌雄表达水平相当。这些结果表明BmPBP2和BmPBP3可能起着性信息素识别的作用。

Identification and expression pattern of two pheromone binding proteins in silkworm, Bombyx mori

Olfaction plays an important role in insect behaviors for survival and reproduction. In this study, we obtained two cDNA fragments encoding two silkworm pheromone binding proteins, named BmPBP2 and BmPBP3, respectively. Together with already reported silkworm PBP1 and two general odorant_binding proteins (GOBPs), all these five genes, consisting of three exons, have conserved exon/intron boundary and six characteristic cysteines. Of them, the three PBP genes are present in tandem arrays. Homology analysis showed that the BmPBP2 and BmPBP3 had about 69% and 63% identity with PBPs from Manduca sexta, respectively. Semi-quantitative RT-PCR analysis indicated that BmPBP2 and BmPBP3 were specific expressed in female and male antennae with the same level. These results show that BmPBP2 and BmPBP3 are possibly involved in pheromone detection and discrimination.