The TERT gene provides instructions for making one component of an enzyme called telomerase. Telomerase maintains structures called telomeres, which are composed of repeated segments of DNA found at the ends of chromosomes.
How is hTERT regulated?
This suggests that expression is regulated by changes in the rate of hTERT gene transcription. In tumor cell lines hTERT expression behaves like a recessive trait, indicating that lack of expression in normal cells is due to one or several repressors.
Does telomerase synthesize DNA?
Some cells have the ability to reverse telomere shortening by expressing telomerase, an enzyme that extends the telomeres of chromosomes. Telomerase is an RNA-dependent DNA polymerase, meaning an enzyme that can make DNA using RNA as a template.
Do humans express telomerase?
Most human somatic cells do not produce active telomerase and do not maintain stable telomere length with proliferation. Most or all do have telomerase RNP, which raises the possibility of a second telomerase function independent of DNA synthesis.
Is hTERT a gene?
Since the catalytic component of telomerase is its reverse transcriptase, hTERT, and the RNA component hTERC, hTERT is an important gene to investigate in terms of cancer and tumorigenesis. The hTERT gene has been examined for mutations and their association with the risk of contracting cancer.
What are hTERT cells?
Human telomerase reverse transcriptase (hTERT)–immortalized primary cells represent a breakthrough in cell biology research that combines the in vivo nature of primary cells with the traditional cell line’s ability to survive continuously in vitro.
What does the hTERT gene do?
hTERT is often up-regulated in cells that divide rapidly, including both embryonic stem cells and adult stem cells. It elongates the telomeres of stem cells, which, as a consequence, increases the lifespan of the stem cells by allowing for indefinite division without shortening of telomeres.
What is hTERT promoter?
Human telomerase reverse transcriptase (hTERT) is the catalytic subunit of telomerase, whose expres- sion is strictly regulated dependently upon cell types. hTERT is shown to be expressed in cancer cells, but not in most normal cells. Thus, the hTERT promoter is thought to be useful for specific cancer therapy.
How does telomerase add DNA?
Telomerase adds complementary RNA bases to the 3′ end of the DNA strand. Once the 3′ end of the lagging strand template is sufficiently elongated, DNA polymerase adds the complementary nucleotides to the ends of the chromosomes; thus, the ends of the chromosomes are replicated.
Why is telomerase important in DNA replication?
Telomeres are the physical ends of eukaryotic chromosomes. They protect chromosome ends from DNA degradation, recombination, and DNA end fusions, and they are important for nuclear architecture. Telomeres provide a mechanism for their replication by semiconservative DNA replication and length maintenance by telomerase.
Why do humans need telomerase?
Expression of telomerase is usually required for cell immortalization and long-term tumor growth. In humans, telomerase activity is tightly regulated during development and oncogenesis. The modulation of telomerase activity may therefore have important implications in antiaging and anticancer therapy.
What is the role of telomerase in the human body?
Telomerase is the enzyme responsible for maintenance of the length of telomeres by addition of guanine-rich repetitive sequences. Telomerase activity is exhibited in gametes and stem and tumor cells. Besides catalytic telomere elongation, independent telomerase functions can be also involved in cell cycle regulation.
