Calreticulin, a Calcium-binding Molecular Chaperone, Is Required for Stress Response and Fertility in Caenorhabditis elegans

Abstract

Calreticulin (CRT), a Ca2+-binding protein known to have many cellular functions, including regulation of Ca2+ homoeostasis and chaperone activity, is essential for heart and brain development during embryogenesis in mice. Here, we report the functional characterization of Caenorhabditis elegans calreticulin (crt-1). Acrt-1 null mutant does not result in embryonic lethality but shows temperature-dependent reproduction defects. In C. elegans CRT-1 is expressed in the intestine, pharynx, body-wall muscles, head neurons, coelomocytes, and in sperm. crt-1males exhibit reduced mating efficiency and defects late in sperm development in addition to defects in oocyte development and/or somatic gonad function in hermaphrodites. Furthermore, crt-1 anditr-1 (inositol triphosphate receptor) together are required for normal behavioral rhythms. crt-1transcript level is elevated under stress conditions, suggesting that CRT-1 may be important for stress-induced chaperoning function inC. elegans.