- Telomeres transcribe
information just like the way DNA does
- The RNA that are
transcribed from the telomeres are called TERRA.
function of the TERRA is essential to preserving telomeres.
found at the end of DNA strands, they act as a buffer for the DNA strands and
- Protecting the DNA from
- Fusion with
other strands of DNA
are short tandem repeats of DNA and in
humans they are repeated 3,000 times and extend to about 15,000 base pairs.
There is a shortening of the length of telomeres on every DNA replication.
‘TERRA could play a significant role in telomere protection and can help in increasing human lifespan.’
Telomeres aid in
protecting the DNA strand from unnecessary recombination and from the DNA
strand ends from fusing. However, on every replication, the length of the
telomeres are reduced by 20 base pairs. The telomeres continue to reduce in
size resulting in a point where the length of the telomeres is reduced to a
crucial length.This stops the process of replication and the cell dies through
a process called apoptosis. The end of replication and the death of the cell
increases as we age and aging cells lead to an aging body.
Telomerase is an
enzyme that is responsible for adding the telomere segments TTAGGG to the ends
of the chromosome. This enzyme is present in small quantities in somatic cells
of normal individuals, which is responsible for the aging of these cells.
present in higher quantities in germ cells as these cells need to sustain their
DNA replication and grow into specialized cells.
found in large quantities in cancer cells and this is the reason behind the
immortality of these cells and the rapid cell division that takes place.
the Shortening of Telomeres
: Obese people have a higher risk of reduction in telomere length
due to oxidative stress and DNA damage. Studies have shown that there is nearly
8.8 years reduction in lifespan among obese individuals when compared with lean
individuals. Smoking: Smoking reduces the length of
the telomeres and excessive smoking correlates with telomere damage. Stress:
Stress has found to increase damage to telomere length, resulting in
shortening.Environmental factors: Certain environmental factors and pollutants could lead to
shortening of the telomere length.
The research team led by Maria A. Blasco and colleagues from the Spanish National Cancer
Research Centre have found that these tightly packed structures transcribe RNAs
that are essential to preserving these repeats. These RNA are called TERRA. The
scientists have also identified the region of the genome where these molecules
Study on Mice
Maria A. Blasco
and colleagues studied the TERRA region in mice and found that they were
produced in the pair of chromosome 19 and to a lesser extent in chromosome 9.
Study on Humans
The study is
published in Nature Communications
and details the location of the
chromosome from where TERRA are produced. 18 RNA that were earlier thought to be TERRA were studied, however TERRA were produced in the
- Long arm of chromosome 20 (20q)
arm of chromosome X(Xp)
verified whether these two regions were significant in the production of TERRA
by using the CRISPR-CAS9 system to cut the sites of TERRA production from these
showed that the suppression of the chromosome Xp did not have any significant
effect on the production of telomeres. However, the suppression of chromosome
20q showed a drastic effect on telomeres.
of 20q as one of the major locus for human TERRA generation allows us to
address the role of TERRA telomere biology," say the authors who continue
to study telomeres. The researchers studied the effect of removal of TERRA from
cell lines and identified the following
- There was a significant increase in
damage to telomere and DNA
- There was an increase in
Dr Basco says
"These results are striking because they clearly demonstrate that TERRA
play an essential role in cell viability as well as in preserving telomeres;
they are just as important to the functioning of telomeres as telomerase or
shelterins, the proteins that protect the telomeres."
Highlights of the Study
- This study provides the first
conclusive evidence about the importance of TERRA in protecting telomeres and
is the first of its kind studied on any organism.
region production is mapped to the chromosome 20q.
study highlights the importance of TERRA in preserving telomeres. It also
associated chromosome 20q to TERRA. This will help in understanding disorders
that occur due to alterations in this region of the chromosome.
disorders that occur in telomeres have not been associated with telomerase as
well as in shelterins. The malformations in TERRA could be studied for these
- The effect of TERRA on telomere length can be
probed and this could open prospective doorway for studies on aging and
increasing the lifespan of humans.
- The effect of TERRA on
the telomere of cancer patients is another area that would benefit medical
- Telomeres, lifestyle, cancer, and aging -
- What is a telomere? - (http://www.yourgenome.org/facts/what-is-a-telomere)
- TERRA, the RNAs that protect telomeres -