Artemin, a Diapause-Specific Chaperone, Contributes to the Stress Tolerance of Artemia Cysts and Influences Their Release from Females.

The Journal of experimental biology

PubMedID: 24526727

King AM, Toxopeus J, MacRae TH. Artemin, a Diapause-Specific Chaperone, Contributes to the Stress Tolerance of Artemia Cysts and Influences Their Release from Females. J Exp Biol. 2014;.
Females of the crustacean, Artemia franciscana produce either motile nauplii or gastrula stage embryos enclosed in a shell impermeable to nonvolatile compounds and known as cysts. The encysted embryos enter diapause, a state of greatly reduced metabolism and profound stress tolerance. Artemin, a diapause-specific ferritin homologue in cysts has molecular chaperone activity in vitro. Artemin represents 7.2% of soluble protein in cysts, about equal to the amount of p26, a small heat shock protein (sHsp). However, there is almost twice as much artemin mRNA in cysts as compared to p26 mRNA suggesting that artemin mRNA is translated less efficiently. RNA interference (RNAi) employing the injection of artemin double stranded RNA (dsRNA) into the egg sacs of Artemia females substantially reduced artemin mRNA and protein in cysts. Decreasing artemin diminished desiccation and freezing tolerance of cysts, demonstrating a role for this protein in stress resistance. Knock down of artemin increased the time required for complete discharge of a brood of cysts carried within a female from a few hours up to 4 days, an effect weakened in successive broods. Artemin, an abundant molecular chaperone, contributes to stress tolerance of Artemia cysts while influencing their development and/or exit from females.