Mechanisms of DNA repair

1. Mechanisms of DNA repair
Karen Hidalgo Carrillo
III Semester
Faculty of Medicine
Pontificia Bolivariana University

2. The reparation of
DNA
By:
Karen Hidalgo Carrillo
Teacher:
Lina María Martínez.
University:
Pontificia Bolivariana University
Bibliography
• JCI Journals. "New gene mutation
associated with defective DNA
repair and Fanconi anemia."
ScienceDaily. ScienceDaily, 10 July
2017.
<www.sciencedaily.com/releases/2
017/07/170710161001.htm>.
• BMJ. "Night shifts may hinder
body's ability to repair DNA
damage: Suppression of sleep
hormone melatonin likely factor,
findings suggest." ScienceDaily.
ScienceDaily, 26 June 2017.
<www.sciencedaily.com/releases/2
017/06/170626190613.htm>.
• MARTINEZ SÁNCHEZ, Lina María.
Biología molecular. 8. ed. Medellín:
UPB. Fac. of Medicine, 2015. 109-
115 p.
Medical utility
It's very important to identify different factors
that affect the DNA repair mechanisms,
because they can find new markers that can be
used from the clinic helping to identify the
different enzymatic and compounds alterations
that can influence the DNA repair.
Also, they can find new medical treatments for
the different illness caused by DNA repair
alterations and some treatments for cancers;
and new objectives of genetic therapy that can
help people who have this alterations.
Additionally in the future,
we can use campaigns to
preventing and
promoting to avoid
activities and actions that
can increase the incidence
of this illness, and to
make known the
importance to have good
night sleep hours and
teach the community all
the consequences that
they can have if they
realize night works.

3. Introduction Night shifts may hinder
body’s ability to repair
DNA damage
New gene mutation
associated with defective
DNA repair and Fanconi
anemia
- Direct reversal repair mechanism: to correct
pyrimidine dimers and alkylated guanine residues.
- Cleavage mechanisms: includes NER and BER
- Double strand mechanism: it can be homologous
recombination's mechanism or non-homologous
terminal binding mechanism.
A failure in one of these mechanisms can cause
cancer and different illness, for example: xeroderma
pigmentosum and cockaynes syndrome (for a failure
in NES) and anemia of fanconi ( for a failure on
repair of double strand breaks), and others.
All days, our cells are exposed
to different factors that affect
the DNA structure, for that,
the cells have different
mechanisms to repair the
damage DNA, and this
mechanisms play an
important role in protecting
the body against cancers and
tumors.
Within the main mechanisms
that the cell have to repair
DNA, we find:
The Fanconi anemia is associated to a damage in the
repair of double strand breaks for Homologous
recombination, caused by mutation in one of 20
known genes.
They reported a case of a children that has the
Fanconi anemia symptoms and they find a mutation
in a new gene, the gene FRWD3 which encodes an
enzyme that helps target other proteins for
degradation, causing defects in the DNA repair.
The 8-OH-dG is a chemical byproduct of active DNA
repairing. The levels in the urine of 8-OH-dG are
lower on people that work at night and have day
sleep than people who have normal night sleep.
They thing this difference is associated to production
of the "sleep hormone" melatonine because this
hormone is not produce normally on people who
have day sleep. But, other factors influence in levels
of 8-OH-dG, for example alcohol and the short
duration of sleep.
Melatonin boosts the activity of the genes involved
in the NER pathway that repair the oxidative DNA
damage produced for the normal cell metabolism.
Personal comment: The DNA
repair is an important factor to
keep the correct information
and the correct function of cells.
If we find some factors to are
damaging this repair mechanism
of DNA we can find solutions to
prevent the cancer and other
illness associated to DNA
mutation.
Personal comment: It's so important find new
genes that codify to enzymes that are implicated in
DNA repairing mechanisms because it give us a
new way to focus a future studies to treat some
illness associated to fails in this genes.

4. Introduction
The cells are submitted every time to factors that
cause DNA alterations and mutations, for this
reasons the cells have had to develop DNA
repairing mechanisms to keep the correct genetic
information's and prevent the development and
proliferation of mutated cells that can origin
cancers and others illness.
If the cells have alterations in this DNA repair
mechanisms they will suffer apoptosis or will
generate cancers. For that is very important to
study the different external and physiological
factors that can affect genes and proteins to
participate in this mechanisms.

5. Night shifts may hinder body’s
ability to repair DNA damage
The 8-OH-dG is a chemical byproduct of active DNA
repairing. The levels in the urine of 8-OH-dG are lower
on people that work at night and have day sleep than
people who have normal night sleep. They think this
difference is associated to production of the "sleep
hormone" melatonine because this hormone is not
produce normally on people who have day sleep. But,
other factors influence in levels of 8-OH-dG, for example
alcohol and the short duration of sleep.

6. Night shifts may hinder body’s
ability to repair DNA damage Normal cell metabolism produces
oxygen free radicals and this
radicals act in the DNA causing
damage, and for that the cell must
have different mechanisms to find it
and repair the damage DNA.
Melatonin boosts the activity of the
genes involved in the NER pathway
that repair the oxidative DNA
damage.

7. Night shifts may hinder body’s
ability to repair DNA damage
Types of DNA repair
Direct reversal
repair mechanism
Cleavage
mechanisms
Double strand
mechanism
Includes
are
NER
BER
Repair nucleotides
Repair bases

8. Night shifts may hinder body’s
ability to repair DNA damage
The investigators think that
the diet and the level of the
circulating antioxidant are an
other important factor to the
lower levels of 8-OH-dG in
urine.

9. Personal
comment
Night shifts may
hinder body’s
ability to repair
DNA damage
The DNA repair is an important
factor to keep the correct
information and the correct
function of cells. If we find some
factors to are damaging this
repair mechanism of DNA we can
find solutions to prevent the
cancer and other illness
associated to DNA mutation.
It is very interesting to see how
melatonin is implicated in the
DNA reparation and the others
effects that the melatonin have
apart to control the Sleep-wake
cycle in prevent some cells
mutations of the DNA and
because of that it can prevent
some cancers and illness.

10. New gene mutation associated
with defective DNA repair and
Fanconi anemia
They reported a case of a children
that has the Fanconi anemia
symptoms and they find a mutation
in a new gene, the gene FRWD3
which encodes an enzyme that helps
target other proteins for
degradation, causing defects in the
DNA repair.

11. New gene mutation associated
with defective DNA repair and
Fanconi anemia
The Fanconi anemia is
associated to a damage in
the repair of double
strand breaks for
Homologous
recombination, caused by
mutation in one of 20
known genes.

12. New gene mutation associated
with defective DNA repair and
Fanconi anemia
The repair of double strand
breaks
Can be
1. Homologous recombination's
mechanism
2. Non-homologous terminal binding
mechanism
The reparation is in
based of the
homologous DNA
The reparation is from
the same DNA strand
Where
Where

13. New gene mutation associated
with defective DNA repair and
Fanconi anemia
The same genes that are implicated in the
Fanconi anemia are encoded to factors
that are very important to the DNA repair,
for that reason this genes have an
important role in the susceptibility on this
individuals to contract different types of
cancer
Cancer cell

14. Personal
comment
New gene mutation
associated with
defective DNA
repair and Fanconi
anemia
It's so important find new genes that
codify to enzymes that are implicated
in DNA repairing mechanisms
because it give us a new way to focus
a future studies to treat some illness
associated to fails in this genes. This
types of investigations allows make a
new orientation of the genetic
therapies and give more options of
medical treatments for the patients
who have some illness relationated
for wrong DNA repair.

15. Medical utility
It's very important to identify
different factors that affect the DNA
repair mechanisms, because they can
find new markers that can be used
from the clinic helping to identify the
different enzymatic and compounds
alterations that can influence the
DNA repair.
And with these markers the
laboratories can make new tests to
identify some deficiencies of the DNA
repair mechanisms more easily and
the doctors would make better
diagnosis.

16. Medical utility
The researches can find new medical
treatments for the different illness
caused by DNA repair alterations and
some treatments for cancers, for
example, they can use medicines that
can replace the enzymes and
proteins that are affected in this
alterations.
And researches also can have new
objectives of genetic therapy to help
people who have this DNA repair
alterations.

17. Medical utility
In the future, we can use campaigns to preventing and
promoting to avoid activities and actions that can increase the
incidence of this illness, and to make known the importance to
have good night sleep hours and teach the community all the
consequences that they can have if they realize night works.

18. Medical utility
In conclusion, as the cells are daily subject to
different factors that can damage the DNA
(for example ultraviolet light, radiation,
cigarette smoke, and others) the mechanisms
that cells use to repair this DNA play an
important role not only in the treatment of
illnesses but in the prevention and diagnosis
of them, because it produce some molecules
that we can measure, and that is very
important for the medical application.

19. • JCI Journals. "New gene mutation
associated with defective DNA repair and
Fanconi anemia." ScienceDaily.
ScienceDaily, 10 July 2017.
<www.sciencedaily.com/releases/2017/07/
170710161001.htm>.
• BMJ. "Night shifts may hinder body's
ability to repair DNA damage: Suppression
of sleep hormone melatonin likely factor,
findings suggest." ScienceDaily.
ScienceDaily, 26 June 2017.
<www.sciencedaily.com/releases/2017/06/
170626190613.htm>.
• MARTINEZ SÁNCHEZ, Lina María. Biología
molecular. 8. ed. Medellín: UPB. Fac. of
Medicine, 2015. 109-115 p.