Cockx, Bram et al. (2021) International Worm Meeting "Peptidergic modulation of dispersal behavior in pathogenic and free-living nematodes"

Beets, Isabel, Dalzell, Johnathan, Lee, Junho, Yang, Heeseung, Van Bael, Sven, Vandewyer, Elke, Kieswetter, Amanda, Boelen, Rose, Cockx, Bram, Temmerman, Liesbet

[International Worm Meeting, 2021]

Emerging evidence suggests that behavioral changes associated with host finding of pathogenic nematodes may be regulated by neuropeptides. Hence, we started from peptidomic discovery in such a species, Steinernema carpocapsae, to direct functional discovery. We observe numerous similarities between the well-studied C. elegans peptidome and the S. carpocapsae peptidome, which we further exploit to understand neuropeptidergic contributions to regulating nictation, an evolutionary conserved behavior for foraging in (these) nematodes. An in-house method based on acidified methanol was used to extract endogenous neuropeptides of Steinernema carpocapsae infective juveniles, a life stage similar to the C. elegans dauer stage. Neuropeptide identification was done by state-of-the-art UHPLC-MS/MS. We detected 30% (139) of the predicted peptidome in these infective juveniles, which provides a resource for comparison with the C. elegans dauer peptidome (in house). We hypothesized that nictation-relevant peptides will be abundant in infective juveniles and/or dauers, and prioritized these for functional assays. Out of several tested target genes, we found at least one neuropeptidergic signaling system that is involved in modulation of nictation behavior, which we assayed using microdirt arenas. In addition, using phylogenetic analyses, we aim to get a better global understanding of conserved peptidergic signaling systems in parasitic and free living nematodes. Steinernema spp. are used as eco-friendly alternative for chemicals to combat pest insects. Knowledge on neuropeptidergic regulation of host-finding strategies will help understand how entomopathogenic nematodes regulate their behavior. This should contribute to improving their applicability and host specificity in the field.

K Morita et al. (1999) International C. elegans Meeting "CeBRAM-1A and CeBRAM-2B, new signal mediators of TGF-b signaling pathways in the C. elegans"

N Ueno, K Morita, M Shimizu, S Yoshida, H Shibuya, M Mochii

[International C. elegans Meeting, 1999]

TGF-b family of growth factors regulate many aspects of cellular function. The signaling is common in diverse animal species from vertebrates to C. elegans. We have been interested in the signaling pathway of the TGF-b family. We reported about cloning of a full-length cDNA (0.9 kb) of CeBRAM-1A (We previously called CeBRAM-2 ), a DAF-1 binding protein (WBG 15 (3): 38). HA-tagged CeBRAM-1A transiently expressed in COS7 cells was found to bind type I receptors, both ALK-3 (mammalian) and DAF-1 (C. elegans). CeBRAM1A;;GFP fusion protein was found to be expressed dominantly in amphid and pasmid neurons (e.g. ASI, ASK, ASJ, etc.). Subsequently, the null mutant was created by Tc1 deletion method. The CeBRAM-1A null mutant had the genetic interaction with mutants in daf-7 TGF-b pathway by examining dauer formation of the double mutants. These results suggest that CeBRAM-1A is involved in the daf-7 TGF-b pathway in C elegans as a negative regulator. We have now identified another human BRAM-1 homologue, CeBRAM-2B, in C. elegans. CeBRAM-1A and CeBRAM-2B have 66% amino acid identity and are conserved extremely in the carboxy-terminal region which seems to be necessary for binding to the type I receptor. Interestingly, double strand RNA interference (dsRNAi) of CeBRAM-2B showed Lon phenotype. These results indicate the possibility that CeBRAM-2B is involved in the cet-1/dbl-1/sma pathway of another TGF-b signaling. We are currently trying to identify the CeBRAM-2B null mutant by TMP-UV method.