Cellular defense against fatal associations between proteins and DNA Date: July 3, 2014 DNA 'replication fork' reconstituted for the first time Date: July 9, 2014

1. CELLULAR DEFENSE AGAINST FATAL
ASSOCIATIONS BETWEEN PROTEINS AND
DNA AND DNA “REPLICATION FORK”
RECONSTITUTED FOR THE FIRST TIME
Laura Quintero Gutiérrez
Medical student
3rd semester
Molecular Biology

4. INTRODUCTION
Through studies made since XIX
century, was possible to discover that
the molecules of DNA are carriers of the
genetic information .
The Chromosomes contents the linear
DNA molecules and they are compound
by histones and DNA molecules.
The DNA needs to be processed and a
very important part of processing is the
replication.
The DNA acquires a tridimensional
structure that can be modified and
causes alterations in the health.

5. CELLULAR DEFENSE
AGAINST FATAL
ASSOCIATIONS BETWEEN
PROTEINS
AND DNA
July 3, 2014

6. NEW 1
DNA is very
vulnerable to
various types of
damages. These
damages can
cause the
crosslinking of
proteins to DNA
Some types of
DNA damages are
caused by X rays,
Gamma rays, UV
radiations or
spontaneous
alterations.
Furthermore, the
DNA-proteins
cross link interfere
with the
replication
process.

7. NEW 1
In the process of
replication, one
brand of DNA
synthesizes a new
one, and then we
will have two
daughter brands of
DNA. It occurs in S
phase of cellular
cycle.
To do the
replication, the cells
needs to unwind
and separate de
DNA double helix
with the
topoisomerase and
helicase, so these
enzymes may be
blocked by DPCs
and the cell doesn’t
replicate the DNA.

8. NEW 1
The block of these
enzymes is a way to
inhibit the replication
and avoid the
alterations of DNA,
caused by DNA-
proteins crosslink
However, the
protease Wss 1 has
the capacity to
remove the DNA-
proteins crosslinks,
only in presence of
DNA, so the
replication can
continue and the
damages of DNA will
not affect the
replication and the
genetic information

9. The finding of a new
enzyme with these
characteristics is a good
tool to attend diseases
that are caused by
modifications in DNA as
cancer, and to avoid
using aggressive
therapies that
deteriorate the quality of
life of people with
cancer.
NEW 1 OPINION
I think this kind of findings may
improve the knowledge about DNA
processing and therapy of illness.

10. DNA 'REPLICATION FORK'
RECONSTITUTED FOR
THE FIRST TIME
JULY 9, 2014

11. NEW 2
The replication is a
fundamental step in the
cycle of cells and it has a
important part: The unzip
of double stranded DNA
and to create a daughter
copies
The replication is a
semiconservative
process, because a
original brand is
conserved in the
daughter brand.
For the replication process the cell needs enzymes as
polymerase DNA, ORI, fork replication, Okazaki fragment.
DNA ligase, helicase, SSDBP, RNAasa H and topoisomerase.

12. NEW 2
The principal enzyme of replication is the DNA
polymerase, it catalyzes the bonds of dNTP to
originate the DNA strand
• The replication fork is the active region of DNA
synthesis. In this point the strands are separated
and the new daughter brands are synthesized
The new brand are synthesized by polymerase delta
and polymerase epsilon. The synthesis of two
daughter brands occurs in a discontinuous form. To
do this a new primer are needed.

13. NEW 2
To know in detail how
the process works
O’Donnell brought
essential enzymes,
nucleotides and linear
molecule of duplex
DNA
Then, the found
features of
polymerase
delta and
polymerase
epsilon
Epsilon,
doesn’t attach
very well to
DNA, it
requires CMG
complex
Delta, , binds
very strongly
to the PCNA
clamp (protein
that encircles
DNA)

14. NEW 2 OPINION
The developing of
new tools to
understand the
DNA processing is
a big step in the
science
It could be the
solution and the
answer to many
difficult situations
in the health field.
To know how really
works the DNA
replication, provide
to the scientist and
doctors more clues
about the
treatment or cure
of most aggressive
diseases.

15. MEDICAL UTILITY
The growths often invade
surrounding tissue and
can metastasize to distant
sites.
Cancer is the uncontrolled
growth and spread of
cells. It can affect almost
any part of the body.

16. MEDICAL UTILITY
Many cancers can be prevented by
avoiding exposure to common risk
factors, such as tobacco smoke
In addition, a significant proportion of
cancers can be cured, by surgery,
radiotherapy or chemotherapy,
especially if they are detected early.
Some people use chemotherapy
(chemo) to eliminate cancerous cells,
to decrease the symptoms or pain,
but chemo is very aggressive

17. MEDICAL UTILITY
Chemotherapy is the use of
drugs to kill bacteria, viruses,
fungi, and cancer cells. Most
commonly, the term is used to
refer to cancer-killing
drugs. Chemotherapy drugs
can be given by mouth or
injection. Because the
medicines travel through the
bloodstream to the entire
body, the majority of
administered chemotherapy is
considered a body-wide
(systemic) treatment

18. MEDICAL UTILITY
However, some normal
cells -- including those
found in the bone
marrow, hair, and the
lining of the
gastrointestinal tract --
also divide very quickly.
Chemotherapy can
also damage or kill
these healthy cells.
The findings of the news
can be a good tools to
avoid the side effects of
chemo, so, the people will
not develop cancer and the
people with cancer will be
right.

19. BIBLIOGRAPHY
Max-Planck-Gesellschaft. "Cellular defense against fatal associations
between proteins and DNA." ScienceDaily.
www.sciencedaily.com/releases/2014/07/140703142350.htm (accessed
July 19, 2014).
Rockefeller University. "DNA 'replication fork' reconstituted for the first
time." ScienceDaily.
www.sciencedaily.com/releases/2014/07/140709100106.htm (accessed
July 18, 2014)
Perry MC. Approach to the patient with cancer. In: Goldman L, Schafer AI,
eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier;
2011:chap 182.
http://www.nlm.nih.gov/medlineplus/ency/article/002324.htm
World Health Organization, Cancer. http://www.who.int/topics/cancer/en/
MARTINEZ SÁNCHEZ, Lina María. Biología molecular. 7. ed. Medellín:
UPB. Fac. de Medicina, 2012. 78 p.