Calumenin is a Ca<SUP>2+</SUP> binding protein containing EF-hand motif, localized to the secretory pathway. Perturbed level of calumenin is casually associated with several diseases such as cancer, atherosclerosis and drug resistance. However, the physiological role of calumenin is largely unknown. Caenorhabditis elegans calumenin shows 45% identity and 64% similarity with its human counterpart. We are characterizing the C. elegans deletion mutant,
tm1783, in which approximately 200bp of 5 prime upstream region followed by the initial two exons of calumenin homolog, M03F4.7 are deleted. Combination of RT-PCR and western blot experiments reveal that
tm1783 is a loss-of-function mutant. Around 37% of the mutants burst at vulva during the transition from L4 to adult molt. Further more,
tm1783 exhibit pleiotropic defects such as decreased brood size, reduced pace of locomotion and slow growth. We are currently investigating its anatomical focus of action utilizing targeted expression of calumenin into hypodermis, body wall muscle or pharynx of
tm1783. To our knowledge, this is the first report of genetic analysis of calumenin.