Osmolarity regulates egg-laying and locomotion of dhs-21(jh129) mutant in Caenorhabditis elegans.

Abstract

DHS-21 is a dicarbonyl/ L-xylulose reductase (DCXR), and it is the only DCXR homolog in Caenorhabditis elegans. dhs-21 gene is expressed in many different parts of tissues including uterine seam (utse) cells, the spermathecal-uterus (sp-ut) valve, intestine, gonadal sheath cells and spermatids. dhs-21(jh129) mutant was acquired which is functionally null mutant. dhs-21(jh129) mutant has decreased brood size, short lifespan, and egg-laying impairment. The egg-retention of dhs-21(jh129) mutant was tested in different osmotic conditions. We hypothesized that since xylitol content may be reduced in dhs-21(jh129) mutant, an osmolyte affecting osmosis, its osmolarity may be lower than N2. Test was performed to find out whether low osmolality NGM might be able to rescue dhs-21(jh129) egg-retention phenotype. I observed that NGM plate with 0mM NaCl indeed rescued egg-retentions of dhs-21(jh129) mutant significantly. Supplementing glycerol levels of dhs-21(jh129) mutant using RNAi against osr-1, osm-7, and osm-11, egg-retention of dhs-21(jh129) mutant was significantly rescued when introduced to osm-7 and osm-11 RNAi. Motility assay was performed to check resistance to osmotic shock, which dhs-21 over-expression line showed more resistance to hyper osmolarity. Checking motility of worms on osmotic stress seems to support the idea that xylitol may act in addition to glycerol to regulate osmolarity in Caenorhabditis elegans