Saina Michael, Busengdal Henriette, Sinigaglia Chiara, Petrone Libero, Oliveri Paola, Rentzsch Fabian, Benton Richard
Faculty of Biology and Medicine, Center for Integrative Genomics, University of Lausanne, Genopode Building, CH-1015 Lausanne, Switzerland.
Sars Centre for Marine Molecular Biology, University of Bergen, Bergen N-5008, Norway.
Nat Commun. 2015 Feb 18;6:6243. doi: 10.1038/ncomms7243.
Insect gustatory and odorant receptors (GRs and ORs) form a superfamily of novel transmembrane proteins, which are expressed in chemosensory neurons that detect environmental stimuli. Here we identify homologues of GRs (Gustatory receptor-like (Grl) genes) in genomes across Protostomia, Deuterostomia and non-Bilateria. Surprisingly, two Grls in the cnidarian Nematostella vectensis, NvecGrl1 and NvecGrl2, are expressed early in development, in the blastula and gastrula, but not at later stages when a putative chemosensory organ forms. NvecGrl1 transcripts are detected around the aboral pole, considered the equivalent to the head-forming region of Bilateria. Morpholino-mediated knockdown of NvecGrl1 causes developmental patterning defects of this region, leading to animals lacking the apical sensory organ. A deuterostome Grl from the sea urchin Strongylocentrotus purpuratus displays similar patterns of developmental expression. These results reveal an early evolutionary origin of the insect chemosensory receptor family and raise the possibility that their ancestral role was in embryonic development.
昆虫味觉和嗅觉受体（GRs和ORs）构成了一个新型跨膜蛋白超家族，它们在检测环境刺激的化学感应神经元中表达。在此，我们在原口动物、后口动物和非两侧对称动物的基因组中鉴定出GRs的同源物（类味觉受体（Grl）基因）。令人惊讶的是，刺胞动物星状海葵中的两个Grl，即NvecGrl1和NvecGrl2，在发育早期，即囊胚期和原肠胚期表达，但在假定的化学感应器官形成的后期阶段不表达。NvecGrl1转录本在反口极周围被检测到，该区域被认为等同于两侧对称动物的头部形成区域。吗啉代介导的NvecGrl1敲低导致该区域的发育模式缺陷，使动物缺乏顶端感觉器官。海胆紫海胆中的一种后口动物Grl显示出相似的发育表达模式。这些结果揭示了昆虫化学感应受体家族的早期进化起源，并增加了其祖先作用是在胚胎发育中的可能性。
