CCC1, putative human checkpoint gene, rescues the DNA damage-inducible G2 checkpoint in yeast
- Baylor College of Medicine, Houston, TX (United States)
- Univ. of Iowa, Iowa City, IA (United States)
- Univ. of Washington, Seattle, WA (United States)
The acquisition of genomic instability characterized by aneuploidy and chromosomal rearrangement is an important step in development of human malignancies. To maintain genomic stability, normal eukaryotic cells from yeasts to humans contain a {open_quotes}checkpoint{close_quotes} mechanism. Incomplete DNA replication or DNA damage results in cell cycle arrest in the G1 and G2 phases of the cycle until the damage is repaired. Mutations in the p53 tumor suppressor gene result in loss of the G1 checkpoint and an increase in genomic instability. Although several genes required for the G2 checkpoint in yeast, including RAD9 and MEC1, have been identified, none of the human genes are known. Our goal is to isolate additional human checkpoint genes as candidate tumor suppressor genes and study their role in tumorigenesis and radiation sensitivity. We developed a genetic strategy to select for human cDNAs by functional complementation of the yeast checkpoint mutations, rad9 and mec1. Screening of a human cDNA library by this method resulted in the isolation of an active clone, CCC1 (checkpoint complementing cDNA), which complements the damage inducible checkpoint of both the rad9 and mec1 mutant strains. We find greater than fifteen fold increases in resistance to ionizing radiation and damage from a mutant DNA ligase when CCC1 is expressed in either the rad9 or mec1 mutant yeast. From preliminary experiments, CCC1 can also rescue the sensitivity of a rad9 strain to UV damage. In contrast, expression of CCC1 has no effect on the HU sensitivity of a mec1 strain suggesting that it acts to complement the damage inducible checkpoint but not the replication checkpoint. Using a microsatellite repeat in the cDNA, CCC1 was mapped by multipoint linkage to an interval at band 14q32 flanked by D14s68 and GATA13B06. Current experiments are directed towards understanding the role of CCC1 in the mammalian checkpoint mechanism of normal and malignant cells.
- OSTI ID:
- 133406
- Report Number(s):
- CONF-941009-; ISSN 0002-9297; TRN: 95:005313-0134
- Journal Information:
- American Journal of Human Genetics, Vol. 55, Issue Suppl.3; Conference: 44. annual meeting of the American Society of Human Genetics, Montreal (Canada), 18-22 Oct 1994; Other Information: PBD: Sep 1994
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BASIC STUDIES
56 BIOLOGY AND MEDICINE
APPLIED STUDIES
PATIENTS
NEOPLASMS
GENES
GENE MUTATIONS
HUMAN CHROMOSOME 14
GENETIC MAPPING
ANEUPLOIDY
CHROMOSOMAL ABERRATIONS
ANIMAL CELLS
CELL CYCLE
MUTAGENESIS
DNA
GENETIC RADIATION EFFECTS
YEASTS
IONIZING RADIATIONS
DNA-CLONING
BIOLOGICAL MARKERS