Identification and Characterization of Two “Sensory Neuron Membrane Proteins” (SNMPs) of the Desert Locust,Schistocerca gregaria(Orthoptera: Acrididae)

Abstract

Pheromone-responsive neurons of insects not only require specific receptors but in addition several auxiliary components, including the “sensory neuron membrane protein,” SNMP. Accordingly, SNMP is considered as a marker for neurons responding to pheromones. For the desert locust Schistocerca gregaria, it is known that the behavior, including aggregation behavior and courtship inhibition, is largely controlled by pheromones. However, little is known about pheromones, their receptors, and the pheromone-responsive cells in locusts. In this study, we have identified two SNMP subtypes, SNMP1 and SNMP2, and compared their phylogenetic relationship and primary structure motifs with SNMPs from other species. Both SNMPs were found in chemosensory tissues, especially the antennae. Employing double in situ hybridization, we identified and localized the SNMP-expressing cells in the antennae. Cells expressing SNMP1 were localized to sensilla trichodea but also to sensilla basiconica, which in locust respond to pheromones. One or a few cells express SNMP1 within the multineuron clusters from sensilla basiconica, whereas the SNMP2 subtype was expressed in cells surrounding the neuron clusters, possibly supporting cells. Based on the finding that SNMP1 is expressed in distinct neurons under chemosensory sensilla, it is conceivable that these cells may represent pheromone-responsive neurons of the desert locust.

Molecular characterization and expression of sensory neuron membrane proteins in the parasitoid Microplitis mediator (Hymenoptera: Braconidae)

“…Generally, SNMP1s are distributed in different types of sensilla. In S. gregaria , S. litura , A. ipsilon , H. virescens and A. polyphemus , SNMP1s are commonly expressed in pheromone‐sensitive sensilla (trichodea and basiconica) (Rogers et al ., , ; Forstner et al ., ; Gu et al ., ; Zhang et al ., ; Jiang et al ., ). In Drosophila , SNMP1 mainly concentrated in the trichoid sensory cilia of antennae, is essential for detecting sex‐pheromone cVA (Benton et al ., ; Jin et al ., ).…”

Under-Expression of Chemosensory Genes in Domiciliary Bugs of the Chagas Disease Vector Triatoma brasiliensis

“…Insect SNMPs are two transmembrane domain-containing proteins in olfactory neurons of antennae and localized in dendrite membranes. They were first identified in the pheromone-sensitive hairs of the wild silk moth Antheraea polyphemus [87] and tobacco hornmoth Manduca sexta [88,89], and now are described in various insect orders namely including Lepidoptera, Coleoptera, Hymenoptera and Diptera [90] and recently Orthoptera [91]. Several functions of insect SNMPs in odorant detection have been predicted (reviewed in [90]) including interactions with pheromone binding protein (PBP)-pheromone complexes, OBP/odorant complexes, OR proteins.…”

Expression of odorant‐binding proteins in mouthpart palps of the desert locust Schistocerca gregaria

“…In fact, a recent study provided strong evidence that OBPs and ORs in the palps are involved in detecting specific odours during the feeding process of locust (Li et al , ). The recent discovery that SNMP1, a marker for pheromone‐sensitive neurons, is also expressed in the palps points to the possibility that some OSNs in the palps may even be responsive for pheromones (Jiang et al , .…”

“…In fact, a recent study provided strong evidence that OBPs and ORs in the palps are involved in detecting specific odours during the feeding process of locust (Li et al, 2018). The recent discovery that SNMP1, a marker for pheromone-sensitive neurons, is also expressed in the palps points to the possibility that some OSNs in the palps may even be responsive for pheromones (Jiang et al, 2016. Double labelling experiments have shown that OBP1 and OBP5, members of the OBP subfamily I-A, were expressed in a low number of cell clusters and in close proximity to Orco-positive cells (Figs 3 and 4). This result implies that OBP1 and OBP5 are expressed in sensilla types housing OSNs, similar to the expression pattern found on the antennae .…”