RAP1GA1: A candidate tumor suppressor locus in 1p36.1
- National Center for Human Research, Bethesda, MD (United States); and others
The rap1/Krev-1 gene (RAP1A) encodes a p21-related protein that suppresses transformation by activated p21{sup ras}. The GTPase activating protein (GAP) gene for p21{sup rap1A} (RAP1GA1) has recently been assigned to chromosome 1p36.1-p35, a region of the genome that is frequently involved in deletions and rearrangements in several different tumors including breast, colon and hepatocellular carcinomas, melanoma, and neuroblastoma. GAP genes negatively regulate the activity of p21 proteins by catalyzing the conversion of the active GTP-bound forms to the inactive GDP-bound forms. The physiological function of p21{sup rap1A}-GAP makes it a strong candidate as a tumor suppressor gene that may have a role in the development of one or more of these malignancies. We have refined the localization of RAP1GA1 by linkage analysis with a highly informative (CA){sub n} repeat contained within the gene, and demonstrated that it is within the minimal deleted region for breast and colon carcinomas, and that it is excluded from the minimally deleted region in melanoma and neuroblastoma. Genetic mapping in the mouse demonstrated that Rap1ga1 is located {approximately}10 cM proximal to Pnd and therefore maps within the interval containing the modifier of Min gene (Mom-1) and the plasmocytoma susceptibility locus (Pcts). The human RAP1GA1 gene contains at least 27 exons. The coding region contains 22 exons, and there are at least five 5{prime}-UT exons that are assembled in a complex pattern of alternative splicing in different tissues. The localization of RAP1GA1 makes it a very strong candidate for a role as a modifier gene involved in the common secondary abnormalities involving 1p36 in several different carcinomas. The potential role of RAP1GA1 in these malignancies is currently being investigated by sequence analysis of breast and colon carcinomas with loss of heterozygosity in 1p36.
- OSTI ID:
- 133338
- Report Number(s):
- CONF-941009--
- Journal Information:
- American Journal of Human Genetics, Journal Name: American Journal of Human Genetics Journal Issue: Suppl.3 Vol. 55; ISSN AJHGAG; ISSN 0002-9297
- Country of Publication:
- United States
- Language:
- English
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