The document discusses DNA repair mechanisms in human lymphocytes. It describes how oxidized purines in DNA are repaired through the base excision repair pathway involving the OGG1 glycosylase. This repair requires activation by the transcription factor NF-YA, which upregulates OGG1 expression when DNA is at risk of oxidation. The repair of oxidized bases by OGG1 in human lymphocytes is slow but can be activated by phytohemagglutinin. Disruption of this global repair of oxidized purines may be due to downregulation of OGG1. A second document discusses how green tea acts as an antioxidant to protect against oxidative stress and influence DNA damage and repair through activation of the Nrf2 transcription factor and upreg

1. KAREN CANO CALLE
Medicine student

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INTRODUCTION
The DNA repair is a set
of processes, that take
care the cell of the
adverse events, like as
defective protein
synthesis.
This defective synthesis
could result in a cellular
aging or diseases.

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DNA REPAIR
ELSEVIER 25 (2015) 1-8

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THE REPAIR OF OXIDIZED PURINES IN THE DNA OF HUMAN
LYMPHOCYTES REQUIRES AN ACTIVATION INVOLVING NF-YA
MEDIATED UPREGULATION.

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THE REPAIR OF OXIDIZED PURINES IN THE DNA OF HUMAN
LYMPHOCYTES REQUIRES AN ACTIVATION INVOLVING NF-YA MEDIATED
UPREGULATION.
The elevated levels of 8-oxoG (a
modificated base) increased GC-
TA mutation frequencies.
The OGG1 (oxoguanina
glicosilasa) repair the oxidized
bases by Base excision repair
(BER), and this one is the major
repair glycosylase for 8oxoG in
eukaryotic cells.

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THE REPAIR OF OXIDIZED PURINES IN THE DNA OF HUMAN LYMPHOCYTES
REQUIRES AN ACTIVATION INVOLVING NF-YA MEDIATED UPREGULATION.
NF-YA is a transcription factor,
and this one is responsible for
the OGG1 regulation when the
DNA is a risk of oxidation, for
example the exposure of cells
to alkylating agent methyl
methanesulphonate.

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THE REPAIR OF OXIDIZED PURINES IN THE DNA OF HUMAN
LYMPHOCYTES REQUIRES AN ACTIVATION INVOLVING NF-YA
MEDIATED UPREGULATION.
The repair of OGG1 in
primary human
lymphocytes is very slow
but can be a efficient repair
with the activation by the
phytohemagglutinin(PHA).
A shutdown of the global
repair of oxidized purines
in lymphocytes must be
to a down-regulation of
the OGG-1

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 In my opinion the regulation of the DNA´s repair is a
essential factor in the maintenance of the DNA
stability, and this allows that the human organism
correct the mutations that can be present by internal
o external factors preventing these mutations lead to
life-threatening diseases.
Student observation

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MUTAGENESIS
(2015) 30 (1): 129-137.
OXFORD

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Redox-linked effects of green tea on DNA damage and repair, and influence of
microsatellite polymorphism in HMOX-1: results of a human intervention trial
The green tea is a
good antioxidant
that can protect
susceptible
individuals at
oxidative stress such
as Type 2 diabetes
patients .
Acts taking part
in the activation
of Antioxidant
(Electrophile)
Response
Element (ARE).

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Redox-linked effects of green tea on DNA damage and repair, and influence of
microsatellite polymorphism in HMOX-1: results of a human intervention trial
The nuclear transcription
factor (Nrf2 ) is a factor
that regulates the
expression of genes
encoding cytoprotective .
Reduced apoptosis
Increses the cell’s survival.
Increased drug resistance.

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 In the organism, there are
various cytoprotective proteins
like the hOGG1 AND THE heme
oxygenase 1 (HMOX-1) , the last
one is a important
cytoprotective protein and this
increased indicated the response
to the oxidative stress.
Redox-linked effects of green tea on DNA damage and repair, and
influence of microsatellite polymorphism in HMOX-1: results of a
human intervention trial

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Redox-linked effects of green tea on DNA damage and repair, and
influence of microsatellite polymorphism in HMOX-1: results of a
human intervention trial
Is suggested that in the microsatellite
polymorphism of HMOX-1 in the GT
repeats is associated with a poorer
protective activity , cells homozygous for
short (n < 25) GT(n) were shown to have
higher HMOX-1 expression after oxidant
challenge than cells homozygous for long (n
≥ 25) GT(n) (13).
the people with a long GT do not respond
efficiently to increased oxidative stress.

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 for my this type of investigations has a very
important relevance in the determination of the
different mechanism whereby the organic
compounds can prevent diseases and also we can to
know the reason whereby these compounds have no
activity in some people.
Student observation

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Medical utility

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 through the knowledge of the beneficial properties, the natural compounds, could
develop natural treatments that prevent diseases .
 This investigations could bring a new diagnostic methods for genetic disorders.
 trying to enhance the expression the factors involved in DNA repair could bring a
cancer`s cure that don´t affect the good cells .
 to improve the patient´s quality life with diseases chronicles.
Medical utility

19.  http://www.nature.com/nchembio/journal/v10/n7/fig_tab/nchembio.1553_F1.html
 http://omicsonline.org/differentiation-of-embryonic-stem-cells-and-oxidative-dna-damage-dna-repair-systems-2157-
7633.S10-005.php?aid=6278
 http://medmol.es/glosario/57/
 Niture SK1, Jaiswal AK.Nrf2 protein up-regulates antiapoptotic protein Bcl-2 and prevents cellular apoptosis.
 http://culturacolectiva.com/campanas-publicitarias-para-la-prevencion-del-cancer-de-mama/
 http://centromedicodepies.
 mx/principal/salud-de-sus-pies/pie-diabetico/
 MARTINEZ,SÁNCHEZ,M,Lina.GRISALES,VARGAS,Natalia.MONTOYA,TORO,Andrés,E.SIERRA,PAMPLONA,Ana,paulina.ORREG
O,QUEVEDO,Esteban.BIOLOGÍA MOLECULAR SÉPTIMA EDICIÓN,Editorial,upb,pág,85-88
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 LIPEN,VON,DER,Carina.SAHU,Sanjeeb.SEIFERMANN,Marco,TIWARI,K,VIJAY The repair of oxidized purines in the DNA of
human lymphocytes requires an activation involving NF-YA-mediated upregulation of OGG1. Institute of Pharmacy and
Biochemistry, University of Mainz, Staudingerweg 5, D-55099 Mainz, Germany Institute of Molecular Biology, D-55218
Mainz, Germany.
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 CHI,WAI,Sin.YEUNG,T,F,Vincent.COLLINS,R,Andrew.BENZIE,F,F,Iris Redox-linked effects of green tea on DNA damage and
repair, and influence of microsatellite polymorphism in HMOX-1: results of a human intervention trial.
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REFERENCES

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THANKS !!!!