Identification of a new allele of .

CATP-4 is a subunit of a Na /K -ATPase important for sperm motility and fertility. Here, we report the characterization of a new allele of isolated from a forward genetic screen for sterile mutants. The allele has a missense mutation that substitutes a highly conserved Glycine which lies close to an ATP binding site. This mutation results in a loss-of-function phenotype comparable to that of the null alleles, emphasizing the importance of this residue for CATP-4 function. This is for the first time that a phenotype has been reported for a single missense mutation in the gene.