What does the hTERT gene do?

What does the hTERT gene do?

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. Telomeres protect chromosomes from abnormally sticking together or breaking down (degrading).

What regulates telomerase activity?

Thus, CHIP may regulate telomerase activity during the cell cycle by controlling the intracellular trafficking and consequently the stability of hTERT [45]. The subnuclear localization of telomerase is also dynamically controlled during the cell cycle and contributes to enzyme regulation [46-48].

What is hTERT in cancer?

hTERT is the rate-limiting component of telomerase, and the upregulated expression of hTERT represents a surrogate marker of increased telomerase activity in most cancers. [8,9] It was hypothesized that the high expression of hTERT can predict the survival of cancer.

Do Normal cells have telomerase?

Telomerase is silent in the vast majority of human tissues and is only expressed in a small number of normal cell types such as dividing male germ-line spermatocytes and a subset of proliferating somatic adult progenitor cells [4].

Is telomerase a tumor suppressor gene?

The repression of telomerase in somatic cells and the resulting telomere proliferation barrier have the hallmarks of a tumour suppressor pathway that limits tumour cell outgrowth after a delay. New evidence, reviewed below, argues that telomere shortening indeed protects against tumour development.

How does the telomerase work?

Telomerase, also called telomere terminal transferase, is an enzyme made of protein and RNA subunits that elongates chromosomes by adding TTAGGG sequences to the end of existing chromosomes. Telomerase is found in fetal tissues, adult germ cells, and also tumor cells.

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.

Where is hTERT found?

chromosome 5
The hTERT gene, located on chromosome 5, consists of 16 exons and 15 introns spanning 35 kb. The core promoter of hTERT includes 330 base pairs upstream of the translation start site (AUG since it’s RNA by using the words “exons” and “introns”), as well as 37 base pairs of exon 2 of the hTERT gene.

How does telomerase play a role in cancer?

Cancer cells often avoid senescence or cell death by maintaining their telomeres despite repeated cell divisions. This is possible because the cancer cells activate an enzyme called telomerase, which adds genetic units onto the telomeres to prevent them from shortening to the point of causing senescence or cell death.

What is the role of telomerase in cancer cells?

Telomerase is a cellular reverse transcriptase that helps to provide genomic stability in highly proliferative normal, immortal, and tumor cells by maintaining the integrity of the chromosome ends, the telomeres. The activity of telomerase is associated with the majority of malignant human cancers.

Which cells have high levels of telomerase?

Embryonic stem cells and undifferentiated embryonal carcinoma (EC) cells display high levels of telomerase activity and hTERT expression, both of which are rapidly downregulated during differentiation (Armstrong et al, 2005) and much lower or absent in somatic cells including stem cells in self-renewal tissues (Figure …

Which cell has the highest telomerase activity?

gut stem cells
For example, gut stem cells or haematopoietic stem cells show highly active telomerase, while telomerase in heart and brain stem cells is far less active, since these organs have a slower turnover rate. The genes for the telomerase subunits in humans are localized at chromosome 5p15 (for TERT) and 3q26 (for TR).

What is the function of telomerase?

Telomerase is a large ribonucleoprotein complex responsible for progressive synthesis of telomeric DNA repeats (TTAGGG) at the 3′ ends of linear chromosomes, thereby reversing the loss of DNA from each round of replication.

What is telomerase and why is it important?

Telomerase has been detected in human cancer cells and is found to be 10-20 times more active than in normal body cells. This provides a selective growth advantage to many types of tumors. If telomerase activity was to be turned off, then telomeres in cancer cells would shorten, just like they do in normal body cells.

What is the difference between telomere and telomerase?

The main difference between telomere and telomerase is that telomere is a protective cap located at the ends of the arms of chromosomes whereas telomerase is an enzyme present in fetal tissues, adult germ cells, and also tumor cells.

What is telomerase made of?

Telomerase, also called telomere terminal transferase, is an enzyme made of protein and RNA subunits that elongates chromosomes by adding TTAGGG sequences to the end of existing chromosomes.

Where is telomerase found?

How do cancer cells turn on telomerase?

And it is turned on when cells become cancerous. Cancer cells may reactivate telomerase by changing the DNA around one of the genes that makes telomerase, called TERT. Barthel is particularly focused on determining how chemical changes to the TERT DNA allow telomerase to be turned on again.

How do cancer cells activate telomerase?

Cancer cells achieve proliferative immortality by activating or upregulating the normally silent human TERT gene (hTERT) that encodes telomerase, a protein with reverse transcriptase activity that complexes with other proteins and a functional RNA (encoded by hTR, also called hTERC) to make a ribonucleoprotein enzyme …

Does telomerase prevent cancer?

Suppressing the activity of telomerase, a telomere‑synthesizing enzyme, and maintaining short telomeres is a protective mechanism against cancer in humans. In most human somatic cells, the expression of telomerase reverse transcriptase (TERT) is repressed and telomerase activity is inhibited.