We describe the cloning of a cDNA from a human testis library that encodes a novel protein with similarity to one repeat of voltage-gated Ca2+ channels (Ca-nu). Northern and dot blot analyses indicate that the novel Ca-nu-like gene is expressed predominantly in testis and at lower levels in many other tissues. Heterologous expression of the Ca-nu-like protein did not lead to the induction of any detectable ionic current and failed to modify intracellular Ca2+ concentrations. Similar one-repeat Ca-nu-like proteins have been. cloned from Bacillus, Mus, and Homo, and appear to encode ion channels involved in renal function, axis determination, and sperm motility. (C) 2003 Elsevier Science (USA). All rights reserved.