A Novel Long Non-Coding RNA in the hTERT Promoter Region Regulates hTERT Expression.

A novel antisense transcript was identified in the human telomerase reverse transcriptase () promoter region, suggesting that the promoter is bidirectional. This transcript, named antisense promoter-associated () RNA, is a 1.6 kb long non-coding RNA. transcription is initiated 167 nucleotides upstream of the transcription start site and is present in both the nucleus and the cytoplasm. Surprisingly, we observed that a large fraction of the polyadenylated RNA is localized in the nucleus, suggesting this might be an additional means of regulating the cellular abundance of hTERT protein. Both and are expressed in immortalized B-cells and human embryonic stem cells but are not detected in normal somatic cells. expression inversely correlates with expression in different types of cancer samples. Moreover, expression is not promoted by an promoter mutation (-124 C>T). Antisense-oligonucleotide mediated knockdown of results in an increase in expression. Conversely, ectopic overexpression of down regulates expression, suggesting a negative role in gene regulation. These observations provide insights into as a novel player that negatively regulates expression and may be involved in telomere length homeostasis.