Differential alternative splicing expressions of telomerase reverse transcriptase in gastrointestinal cell lines

Telomerase is a cellular RNA-dependent DNA polymerase that serves to maintain the tandem arrays of telomeric TTAGGG repeats at eukaryotic chromosome ends. One of the human telomerase components is hTERT, which has three alternative spliced sites that introduce eight isoforms of hTERT mRNA. The expression of these isoforms in gastrointestinal cell lines is unknown. We developed a PCR-based assay for detecting these splicing variants. In gastric and hepatocellular carcinoma cell lines, the gamma deletion variant and its combination variants, alpha- and gamma-, beta- and gamma-, and alpha-, beta- and gamma-deletion variants were frequently detected, while they were not detected in colorectal carcinoma cell lines. Our results provide important information of use for more detailed studies on the regulation of telomerase activity.