Department of Biology, Bowdoin College, 6500 College Station, Brunswick, ME 04011, USA.
Pest Management and Biocontrol Research Unit, US Arid Land Agricultural Research Center, USDA Agricultural Research Services, Maricopa, AZ 85138, USA.
Comp Biochem Physiol Part D Genomics Proteomics. 2019 Jun;30:262-282. doi: 10.1016/j.cbd.2019.03.002. Epub 2019 Mar 7.
Peptides are known to contribute to central pattern generator (CPG) flexibility throughout the animal kingdom. However, the role played by receptor diversity/complement in determining this functional flexibility is not clear. The stomatogastric ganglion (STG) of the crab, Cancer borealis, contains CPGs that are models for investigating peptidergic control of rhythmic behavior. Although many Cancer peptides have been identified, their peptide receptors are largely unknown. Thus, the extent to which receptor diversity/complement contributes to modulatory flexibility in this system remains unresolved. Here, a Cancer mixed nervous system transcriptome was used to determine the peptide receptor complement for the crab nervous system as a whole. Receptors for 27 peptide families, including multiple receptors for some groups, were identified. To increase confidence in the predicted sequences, receptors for allatostatin-A, allatostatin-B, and allatostatin-C were cloned, sequenced, and expressed in an insect cell line; as expected, all three receptors trafficked to the cell membrane. RT-PCR was used to determine whether each receptor was expressed in the Cancer STG. Transcripts for 36 of the 46 identified receptors were amplified; these included at least one for each peptide family except RYamide. Finally, two peptides untested on the crab STG were assessed for their influence on its motor outputs. Myosuppressin, for which STG receptors were identified, exhibited clear modulatory effects on the motor patterns of the ganglion, while a native RYamide, for which no STG receptors were found, elicited no consistent modulatory effects. These data support receptor diversity/complement as a major contributor to the functional flexibility of CPGs.
肽被认为在整个动物界中对中央模式发生器 (CPG) 的灵活性做出贡献。然而，受体多样性/补充在确定这种功能灵活性方面所起的作用尚不清楚。北极滨蟹的脑-咽下神经节（STG）包含CPG，是研究肽对节律行为控制的模型。尽管已经鉴定出许多癌症肽，但它们的肽受体在很大程度上是未知的。因此，受体多样性/补充在该系统中对调节灵活性的贡献程度仍未解决。在这里，使用北极滨蟹混合神经系统转录组来确定整个蟹神经系统的肽受体组成。鉴定出 27 种肽家族的受体，包括某些群体的多个受体。为了提高预测序列的可信度，克隆、测序并在昆虫细胞系中表达了所有atostatin-A、allatostatin-B 和 allatostatin-C 的受体；正如预期的那样，这三种受体都能够转运到细胞膜上。RT-PCR 用于确定每个受体是否在 Cancer STG 中表达。扩增了鉴定出的 46 个受体中的 36 个转录本；这些受体包括除 RYamide 以外的每种肽家族的至少一个。最后，评估了两种未在蟹 STG 上测试过的肽对其运动输出的影响。鉴定出 STG 受体的肌抑制素对神经节的运动模式表现出明显的调节作用，而未发现 STG 受体的天然 RYamide 则没有一致的调节作用。这些数据支持受体多样性/补充是 CPG 功能灵活性的主要贡献者。
