We have analyzed telomeres in four hamster cell lines to investigate how telomeres look in cells grown past the Hayflick limit. In all four cell lines telomeric signals were seen after detection with two different sensitive in situ methods (FISH with PNA probes and PRINS). The telomeric signals were not very strong, suggesting that the repeats are very short, but were nevertheless clearly visible. With the PRINS technique, it was further possible to probe also for the presence of variant telomeric repeats at the chromosome ends. With some of the variant repeat probes, a difference was seen between probes for the C-rich, and probes for the G-rich strand of the repeats. This is similar to findings on normal human chromosomes, and it could therefore be suggested that hamster telomeres are similar to human telomeres in having a discrete domain of variant repeats centromeric to the (AGGGTT) n repeats. Some differences in staining patterns with the variant probes were observed between the various cell lines, but the significance of this finding is unclear. It seems that the telomeres are maintained by telomerase in the cell lines investigeted, as a telomerase assay was positive in all four cell lines.

We have analyzed telomeres in four hamster cell lines to investigate how telomeres look in cells grown past the Hayflick limit. In all four cell lines telomeric signals were seen after detection with two different sensitive in situ methods (FISH with PNA probes and PRINS). The telomeric signals were not very strong, suggesting that the repeats are very short, but were nevertheless clearly visible. With the PRINS technique, it was further possible to probe also for the presence of variant telomeric repeats at the chromosome ends. With some of the variant repeat probes, a difference was seen between probes for the C-rich, and probes for the G-rich strand of the repeats. This is similar to findings on normal human chromosomes, and it could therefore be suggested that hamster telomeres are similar to human telomeres in having a discrete domain of variant repeats centromeric to the (AGGGTT) n repeats. Some differences in staining patterns with the variant probes were observed between the various cell lines, but the significance of this finding is unclear. It seems that the telomeres are maintained by telomerase in the cell lines investigeted, as a telomerase assay was positive in all four cell lines.