Mutations in DNA repair/cell cycle checkpoint genes can lead to the development of cancer. The cloning of human homologs of yeast DNA repair/cell cycle checkpoint genes should yield candidates for human tumor suppressor genes as well as identifying potential targets for cancer therapy. The Schizosaccharomyces pombe genes
rad17,
rad1, and
hus1 have been identified as playing roles in DNA repair and cell cycle checkpoint control pathways. We have cloned the cDNA for the human homolog of S. pombe
rad17, RAD17, which localizes to chromosomal location 5q13 by fluorescence in situ hybridization and radiation hybrid mapping; the cDNA for the human homolog of S. pombe
rad1, RAD1, which maps to 5p14-
p13.2; and the cDNA for the human homolog of S. pombe
hus1, HUS1, which maps to 7p13-
p12. The human gene loci have previously been identified as regions containing tumor suppressor genes. In addition, we report the cloning of the cDNAs for genes related to S. pombe
rad17,
rad9,
rad1, and
hus1 from mouse, Caenorhabditis elegans, and Drosophila melanogaster. These include Rad17 and Rad9 from D. melanogaster,
hpr-17 and
hpr-1 from C. elegans, and RAD1 and HUS1 from mouse. The identification of homologs of the S. pombe rad checkpoint genes from mammals, arthropods, and nematodes indicates that this cell cycle checkpoint pathway is conserved throughout eukaryotes.