NONRADIOISOTOPIC TELOMERIC REPEAT AMPLIFICATION PROTOCOL (TRAP) USINGDIGOXIGENIN-LABELED PROBE

We have attempted to detect telomerase activity by Southern blot analy sis using a digoxigenin labeled probe (5'-(CCCTTA)(6)CCCTAA-3'). Telom erase activity was detected in all cancer cell lines that were tested, and:the lower limit for detection was 10(3) cells. Although telomeras e activity was detected in colon cancer tissues, it was not found in a denoma or normal tissues. Telomerase activity was completely abrogated by heat and RNase treatment of the CHAPS extract. Our results demonst rate that this nonradioisotopic assay is safe and reliable for detecti ng telomerase activity in cancer cell lines and biopsy samples.