ABUNDANCE OF BRCA1 TRANSCRIPTS IN HUMAN CANCER AND LYMPHOBLASTOID CELL-LINES CARRYING BRCA1 GERM-LINE ALTERATIONS

A competitive polymerase chain reaction has been developed for quantit ation of BRCA1 mRNA. In human cancer cell lines, the amount of BRCA1 m RNA is relatively low, ranging from 6 to 38 copies per cell. The decay rate of these transcripts in actinomycin-treated cells indicates that the half-life of these molecules is about 4 hr, suggesting that the l ow concentration of BRCA1 messages is not due to molecular unstability . In human lymphoblastoid cell lines derived from patients carrying ge rm-line alterations of BRCA1, the amount of BRCA1 mRNA per cell is low ered only in cell lines exhibiting alterations leading to specific los s of transcripts from the mutated allele, These data indicate that che amount of BRCAI available in these cells can be related directly to t he number of ''active'' allele. (C) 1997 Wiley-Liss, Inc.