Expression Profile of a γ-Deletion Variant of the Human Telomerase Reverse Transcriptase Gene

Abstract

The human telomerase reverse transcriptase (hTERT) is an essential component of the holoenzyme complex that adds telomeric repeats to the ends of chromosomes. The hTERT transcript has been shown to have two deletion type alternative splicing sites. One deletion site induces the α-deletion variant, lacking 36 by from exon 6, and the other induces the β-deletion variant, lacking 182 by from exons 7 and 8. Here, we identified a novel deletion variant of the hTERT transcript in hepatocellular carcinoma cell lines. The deleted transcript was characterized by an in-frame deletion of 189 bp, spanning nucleotides 2710 to 2898, corresponding to the complete loss of exon 11 (γ-deletion). The region lacking in the γ-deletion lies within RT motifs D and E, suggesting that it is missing conserved residues from the catalytic core of the protein. Both γ- and α-deletion variants were occasionally detected, but the β-deletion variant was frequently observed. Our results may provide important information for more detailed studies on the regulation of telomerase activity.