Calcipressins are a family of calcineurin regulating proteins conserved from fungi to yeast to man. They show binding, inhibiting, and even transcription regulation of the calcium/calmodulin phosphatase calcineurin, and also may play a role in Down Syndrome in humans. A calcipressin homologue,
rcn-1, has been identified in C. elegans on chromosome III in cosmid F54E7. A 3.1 kb upstream region of the genomic DNA of
rcn-1 was cloned into a GFP vector and expression was seen in wild-type worms. Expression was seen mainly in pharyngeal muscle, excretory cells, vulval epithelial cells, ventral and dorsal nerve cords and commissures, head sensory neurons, nerve ring, pre-anal and tail neurons and to a lesser extent in hypodermal cells and intestine. High neuronal and pharyngeal muscle expression is consistent with highly expressed levels of the human homologue DSCR-1 (Down Syndrome Critical Region) in heart and brain in mammals. Polyclonal antibodies were raised against the conserved region of DSCR-1 (Down Syndrome Critical Region ), a human homologue of
rcn-1 in rabbit, and immunostaining with these antibodies was performed in C. elegans. We were able to observe expression in excretory cells, vulval epithelial cells, ventral and dorsal nerve cords and commissures, head sensory neurons, nerve ring, tail neurons, and hypodermal cells. This expression not only confirms our previous GFP expression results, but also shows the conservation of calcipressins from humans to C. elegans. Preliminary data of calcineurin GFP and antibody expression from our laboratory has shown much overlap of expression between
rcn-1 and calcineurin showing a possible relationship between the two proteins. We hope to further delineate this relationship by biochemical analysis of the two proteins. Currently, we are also preparing to raise antibodies against
rcn-1 in rabbit. Northern blot analysis has confirmed a low-level of expression of a 1.0 kb mRNA transcript. We are planning to conduct RNAi of
rcn-1 and will try to obtain deletion mutants by UV-TMP mutagenesis to observe phenotypes.