【目的】昆虫气味受体(odorant receptors,Ors)在其发挥嗅觉识别过程中采用的是配体门控离子通道信号传导机制,这一离子通道是由一个特定的共受体与一个普通气味受体结合为异源二聚体而形成的。其中,气味共受体(odorant receptor coreceptor,Orco)是一个十分独特的家族,在不同种类昆虫中高度保守,并在调控昆虫的嗅觉行为方面发挥关键作用。论文在对中华蜜蜂(Apis cerana cerana,简称中蜂)工蜂Orco研究基础之上,进一步探讨雄蜂Orco的表达特性。【方法】采集中蜂1日龄雄蜂的触角、头(去除触角)、胸、腹、足5部分组织,以及不同发育阶段的幼虫、蛹及成蜂触角。提取各样本的总RNA,利用real-time quantitative PCR(q PCR)技术鉴定Orco在雄蜂不同组织及不同发育时期的表达谱;采集1日龄雄蜂触角制备冰冻切片,合成地高辛标记的寡核苷酸探针,利用原位杂交技术对Orco在雄蜂触角中的表达进行细胞定位分析。【结果】q PCR分析结果表明,Orco转录本在不同组织中的表达量表现为触角〉头〉足〉腹〉胸,其中触角表达量约为头部的100倍;Orco在雄蜂不同发育阶段均有表达,其中幼虫期和蛹期表达量较低,羽化后开始逐渐升高,性成熟后维持在一个较高的水平。此外,结合前期工蜂荧光定量试验数据,分析得到Orco在雄蜂触角中的表达量极显著高于工蜂触角表达量(P〈0.01)。原位杂交结果显示,Orco阳性杂交信号大量表达于雄蜂触角的板型感器和毛型感器的神经元细胞中。【结论】气味受体基因Orco在中蜂雄蜂的触角中大量表达,且在性成熟后表达量达到高峰。结合前期研究结果,推测Orco在中蜂中是偏雄性表达的。
【Objective】 Insect odorant receptors(Ors) adopt a ligand-gated ion channel signal transduction mechanism primarily in olfaction recognition process.This ion channel is formed by a unique Orco protein with a common Ors which are combined to a heterodimer.Odorant receptors coreceptor(Orco) is an unique family,which shares highly conserved gene sequence among different insects and plays a key role in regulating insect behavior.The objective of this study is to research the expression character of Orco in drones of Apis cerana cerana based on the former relevant study in worker bees.【Method】 Five different tissues of antennae,heads(without antennae),thoraces,abdomens and legs from 1-day-old drones,and the larvae,pupae and antennae of adults at different developmental stages were collected.Total RNA of each sample was extracted,and the expression profiles of the Orco in different tissues and at different developmental stages were examined by real-time quantitative PCR(q PCR).Antennae from 1-day-old drones were dissected and the frozen slides were prepared and the digoxigenin-labelled oligonucleotide probes were synthesized.The cellular localization in antennae was detected by in situ hybridization.【Result】q PCR results showed that the expression of Orco m RNA in different tissues were antenna〉head〉leg〉abdomen〉thorax,and it was about 100 times more abundant in antenna than in head.Orco transcripts were detected at all development stages of drones.The expression levels were very low in larval and pupal periods,increased after eclosion,then maintained a higher level during and after sexual maturity stage of drones.Combining with the former data got from the q PCR of worker bees,it showed that the expression level of Orco was significantly higher in drones than in workers.Localization test showed that Orco were largely expressed in neuronal cells of sensilla trihodea and sensilla placodea in antennae.【Conclusion】 This study displayed the odorant receptor gene Orco was predominantly