@article {1397, title = {Evolutionary History of Major Chemosensory Gene Families across Panarthropoda}, journal = {Molecular Biology and Evolution}, volume = {37}, year = {2020}, month = {04/08/2020}, pages = {3601-3615}, abstract = {

Chemosensory perception is a fundamental biological process of particular relevance in basic and applied arthropod research. However, apart from insects, there is little knowledge of specific molecules involved in this system, which is restricted to a few taxa with uneven phylogenetic sampling across lineages. From an evolutionary perspective, onychophorans (velvet worms) and tardigrades (water bears) are of special interest since they represent the closest living relatives of arthropods, altogether comprising the Panarthropoda. To get insights into the evolutionary origin and diversification of the chemosensory gene repertoire in panarthropods, we sequenced the antenna- and head-specific transcriptomes of the velvet worm Euperipatoides rowelli and analyzed members of all major chemosensory families in representative genomes of onychophorans, tardigrades, and arthropods. Our results suggest that the NPC2 gene family was the only family encoding soluble proteins in the panarthropod ancestor and that onychophorans might have lost many arthropod-like chemoreceptors, including the highly conserved IR25a receptor of protostomes. On the other hand, the eutardigrade genomes lack genes encoding the DEG-ENaC and CD36-sensory neuron membrane proteins, the chemosensory members of which have been retained in arthropods; these losses might be related to lineage-specific adaptive strategies of tardigrades to survive extreme environmental conditions. Although the results of this study need to be further substantiated by an increased taxon sampling, our findings shed light on the diversification of chemosensory gene families in Panarthropoda and contribute to a better understanding of the evolution of animal chemical senses.

}, keywords = {antenna-specific transcriptome, BITACORA, chemosensory-related proteins, comparative genomics, Onychophora, Tardigrada}, issn = {0737-4038}, doi = {https://doi.org/10.1093/molbev/msaa197}, url = {https://academic.oup.com/mbe/article/37/12/3601/5880555}, author = {Vizueta, Joel and Escuer, Paula and Fr{\'\i}as-L{\'o}pez, Cristina and Guirao-Rico, Sara and Hering, Lars and Mayer, Georg and Rozas, Julio and S{\'a}nchez-Gracia, Alejandro} } @article {1396, title = {Analysis of Pigment-Dispersing Factor Neuropeptides and Their Receptor in a Velvet Worm}, journal = {Frontiers in Endocrinology}, volume = {11}, year = {2020}, month = {12/05/2020}, pages = {1-21}, type = {Research article}, abstract = {

Pigment-dispersing factor neuropeptides (PDFs) occur in a wide range of protostomes including ecdysozoans (= molting animals) and lophotrochozoans (mollusks, annelids, flatworms, and allies). Studies in insects revealed that PDFs play a role as coupling factors of circadian pacemaker cells, thereby controlling rest-activity rhythms. While the last common ancestor of protostomes most likely possessed only one pdf gene, two pdf homologs, pdf-I and pdf-II, might have been present in the last common ancestors of Ecdysozoa and Panarthropoda (Onychophora + Tardigrada + Arthropoda). One of these homologs, however, was subsequently lost in the tardigrade and arthropod lineages followed by independent duplications of pdf-I in tardigrades and decapod crustaceans. Due to the ancestral set of two pdf genes, the study of PDFs and their receptor (PDFR) in Onychophora might reveal the ancient organization and function of the PDF/PDFR system in panarthropods. Therefore, we deorphanized the PDF receptor and generated specific antibodies to localize the two PDF peptides and their receptor in the onychophoran Euperipatoides rowelli. We further conducted bioluminescence resonance energy transfer (BRET) experiments on cultured human cells (HEK293T) using an Epac-based sensor (Epac-L) to examine cAMP responses in transfected cells and to reveal potential differences in the interaction of PDF-I and PDF-II with PDFR from E. rowelli. These data show that PDF-II has a tenfold higher potency than PDF-I as an activating ligand. Double immunolabeling revealed that both peptides are co-expressed in E. rowelli but their respective levels of expression differ between specific cells: some neurons express the same amount of both peptides, while others exhibit higher levels of either PDF-I or PDF-II. The detection of the onychophoran PDF receptor in cells that additionally express the two PDF peptides suggests autoreception, whereas spatial separation of PDFR- and PDF-expressing cells supports hormonal release of PDF into the hemolymph. This suggests a dual role of PDF peptides\—as hormones and as neurotransmitters/neuromodulators\—in Onychophora.

}, keywords = {BRET, E. rowelli, Ecdysozoa, Epac, Onychophora, Panarthropoda, PDF, PDFR}, issn = {1664-2392}, doi = {https://doi.org/10.3389/fendo.2020.00273}, url = {https://www.frontiersin.org/article/10.3389/fendo.2020.00273}, author = {Martin, Christine and Hering, Lars and Metzendorf, Niklas and Hormann, Sarah and Kasten, Sonja and Fuhrmann, Sonja and Werckenthin, Achim and Herberg, Friedrich W. and Stengl, Monika and Mayer, Georg} }