Excretory gland cell and NSPC genes in C. elegans: investigating their physiological roles.

The nematode Caenorhabditis elegans is one of the best-studied model organisms in molecular biology; however, many aspects of its physiology and the functions of many genes remain poorly understood. In this study, we investigated the role of Nematode-Specific Peptide Family, group C (NSPC) proteins, whose mRNAs were recently identified as primary targets of the poly(A) polymerase TENT-5. Surprisingly, we found that NSPCs are exclusively expressed in the excretory gland cell, a cell with still unclear functionality. Using an optogenetic approach, we precisely ablated the excretory gland cell and observed that, apart from a strong downregulation of NSPCs, nematodes exhibited no transcriptomic or physiological changes in its absence. Additionally, we generated and thoroughly studied a strain with a deletion of all 18 nspc genes, which revealed that, despite previous indications, NSPCs do not influence the worm's defense response. Instead, the transcriptomic analysis showed that the absence of NSPCs results in gene expression changes resembling those observed for DAF-16 mutants, suggesting that NSPCs may somehow influence the key C. elegans insulin signaling pathway. Although further studies are required to explain the exact genetic interaction and elucidate its physiological effects, our findings provide new insights into this unexplored part of nematode physiology.