Animals communicate with each other in aggregating for survival and adaptation. Solitary locusts show an olfactory transition from repulsion to attraction in aggregation. However, the molecular mechanism underlying this transition is less well known. In this study, we explored differentially expressed transcripts (DETs) during locust aggregation and identified that a functional class of general metabolism encompassed the largest number of DETs among all analyzed gene classes. Within this functional class of general metabolism, oxidoreductase mediates synthesis of retinoic acid (RA) from vitamin A and other metabolites derived from carbohydrates. The expression levels of retinaldehyde hydroxylase 1 (raldh1) and retinoid X receptor (rxr), which are two crucial genes for RA synthesis and signaling, were upregulated during 4 h of crowding. Knockdown of raldh1 and rxr by RNA interference (RNAi) in the brains resulted in the loss of olfactory attraction. Moreover, inhibition of RXR by RNAi resulted in downregulated expression of Gna14, a member of the Gα subfamily that transduces signals in G protein-coupled receptor (GPCR) pathways. Abrogating RXR signaling and Gna14 by RNAi knockdown inhibited the function of dopamine receptor 1 (DopR1) and octopamine receptor α1 (OctαR1) in modulating olfactory attraction. RXR signaling is essential for DopR1 and OctαR1 to mediate olfactory attraction. This study showed that RXR signaling mediates attraction by Gα signaling and confirmed a novel link between nuclear receptor RXR and the membrane receptor GPCRs in modulating olfactory attraction.

动物相互交流以求生存和适应。孤独的蝗虫在聚集中表现出从排斥到吸引的嗅觉过渡。然而，这种转变的分子机制尚不为人所知。在这项研究中，我们探索了蝗虫聚集期间的差异表达转录本（DET），并确定了在所有分析的基因类别中，一般代谢的功能类别涵盖了最大数量的DET。在这种一般代谢的功能类别中，氧化还原酶介导维生素A和其他碳水化合物衍生的代谢产物合成视黄酸（RA）。视黄醛羟化酶1（raldh1）和视黄醇X受体（rxr）的表达水平，这是RA合成和信号转导的两个关键基因，在拥挤的4小时内被上调。击倒raldh1和RXR通过在大脑RNA干扰（RNAi）导致嗅觉吸引力的丧失。此外，RNAi对RXR的抑制作用导致Gna14的表达下调，Gna14是Gα子家族的成员，在G蛋白偶联受体（GPCR）途径中转导信号。废除RXR信号和Gna1RNAi敲低4抑制多巴胺受体1（DopR1）和章鱼胺受体α1（OctαR1）在调节嗅觉吸引中的功能。RXR信号对于DopR1和OctαR1介导嗅觉吸引至关重要。这项研究表明，RXR信号通过Gα信号介导吸引力，并证实了核受体RXR和膜受体GPCR之间在调节嗅觉吸引方面有新的联系。