Microsatellite mutation rates are equivalent in normal and telomerase-immortalized human fibroblasts.

Telomerase-expressing human fibroblasts generally have the same properties as normal cells, except that they have an indefinite life span in culture. We have introduced a dinucleotide repeat sequence into the telomerase-expressing hTERT-1604 cell line and characterized the rates and types of frameshift mutations within this microsatellite. These data have been compared with those in diploid fibroblasts with a finite life span. The rates of mutation were found to be similar in the two cell types, indicating that DNA mismatch repair and other cellular processes responsible for maintenance of mutational stability are not disrupted by telomerase immortalization.