Osm-9/OCR-2 can reverse the grk-2 mutation inducing swimming obstacle in C. elegans

Abstract

Caenorhabditis elegans (C. elegans ) has become a pivotal model organism in unraveling the regulatory mechanisms behind rhythmic movement due to its characteristic rhythmic movement pattern. This study aims to explore the mechanism by which the grk-2 mutation causes swimming deficits in C. elegans . In C. elegans , grk-2(gk268) single mutant and grk-2 cDNA transgenetic worms were used to analyze the individual GRK2-associated swimming behaviour. To investigate whether OSM-9 (ortholog of human transient receptor potential cation channel subfamily V) played a role in swimming behavior, the osm-9(yz6) and osm-9(ky10) mutations were introduced into grk-2 mutant worms. And as a contrast, the grk-2(gk268);osm-10(n1602) worms were produced to access the impact of an alternative candidate receptor OSM-10 (a novel protein required for normal osmosensory signal) on the swimming deficits that caused by the grk-2 mutation. And because the OSM-9 requires the OCR-2 (an ortholog of human transient receptor potential cation channel subfamily V member 5) for its proper location in the cell membrane, the grk-2(gk268);ocr-2(ak47) double mutants were established by crossing the ocr-2(ak47) mutant worms with grk-2 mutant worms to investigate the function of OCR-2 in grk-2 mutant worms. Next in order to confirm the functional interaction between osm-9 and ocr-2 in grk-2 mutant worms, the triple mutants of grk-2(gk268);osm-9(ky10);Pocr-2::osm-9 as well as the transgenetic grk-2(gk268); osm-9(ky10);Posm-9::osm-9 were created respectively, Among these groups, the body angels were recorded and quantified to carry out difference analysis. * p < 0.05, ** p < 0.01, *** p < 0.001. The average swimming frequency of grk-2(gk268) single mutants was less than 1 Hz, which was significantly lower than that in wild type animals ( p < 0.001). Contrast to the grk-2(gk268) single mutants, the swimming frequencies in double mutants of grk-2(gk268);osm-9(yz6) and grk-2(gk268);osm-9(ky10) as well as grk-2(gk268);ocr-2(ak47) were significantly recovered (all p < 0.001), while the swimming frequencies of grk-2(gk268);osm-10(n1602) mutants were not improved , suggesting the swimming impairments in the grk-2 mutants in C. elegans were ameliorated by the mutation of osm-9 and ocr-2 but not the mutation of osm-10 . Eventually, the expressions of Pocr-2::osm-9 transgene and Posm-9::osm-9 transgene separately in grk-2(gk268); osm-9(ky10) mutants would evidently down-regulated the swimming ( p < 0.001) when compared with that in the grk-2(gk268); osm-9(ky10) double mutants, which indicated that OSM-9 and OCR-2 exhibit cooperative effects in C. elegans , influencing swimming behavior by modulating GRK-2 activity. In conclusion, loss function of grk-2 will bring into play the inhibitory effect on the swimming by OSM-9/OCR-2 pathway in C. elegans .