Expression of Schizosaccharomyces pombe pho1-encoded acid phosphatase is transcriptionally regulated by adenine and phosphate. Four genes, anr1-3 and anr5, encode negative regulators of pho1 expression. Apart from being designated as loci, the anr genes have not been further characterized. In this study we provide evidence that a strain carrying the deletion of rad24, a 14-3-3 protein-encoding gene, exhibits an anr mutant like the phenotype (higher phosphatase activity, higher transcript levels of pho1, lower sensitivity to adenine of pho1 expression) and that rad24 is closely linked, probably allelic, to anr5. By sequencing the two exons of the rad24 gene in a strain carrying the mutant allele anr5-13, we found a T/A-to-C/G transition in the 225th codon of its ORF, causing a leucine-to-serine substitution in a highly conserved region of all proteins of the 14-3-3 family. anr2 and anr3 are not allelic to rad24. The mutant alleles of anr2 and anr3 are recessive to their wild-type alleles and do not belong to the same epistasis group as rad24.