replication fork and sweet genes(molecular biology folding)
DESCRIPTION
Molecular Biology, Replication Fork, DNA, PDC, Histone AcetylationTRANSCRIPT
Sweet genesSweet genes: New way found by : New way found by which metabolism is linked to the which metabolism is linked to the
regulation of DNAregulation of DNAAND
DNA 'replication fork' reconstituted DNA 'replication fork' reconstituted for the first timefor the first time
Ana Cristina Toro MorenoMedical Student3rd Semester
Molecular Biology 2014-02Universidad Pontificia BolivarianaTeacher: Lina Maria Martínez Sánchez
INTRODUCTIONDNA or Deoxyribonucleic acid is the basis of our genetic code, it contains all the genetic instructions that control cell development and function. Every cell of our body has DNA.
DNA divides , replicating itself, giving two daughter strands, which contain exactly the same genectic instructions as the mother DNA. Then it transcripts into RNA and finally it traduces into proteins. This process is known as the Central Dogma of the genetic information.
The problem remains, in DNA replication. Scientists keep an eye on it, because it is said that most of diseases start in the replication fork, and studying it, may help in the future understand the problems that it can suffer, and help people that has cancer and other diseases to get cure.
DNA ‘REPLICATION FORK’ RECONSTITUDED FOR THE FIRST TIMEJULY 9, 2014– ROCKEFELLER UNIVERSITY
When a cell divides, it first needs to make a copy of its DNA. It replicates into two exact daughter copies.
1Replication is a semiconservative process (old strand and a new strand).
2
Process that occurs in the S phase of cell cycle
3
REPLICATIONHelped by DNA polymerases, enzymes that catalyzes the union of dNTP (deoxyribonucleotids 5’ trifosphates) to create the daughter DNA strand.
In Eukaryotic cells
α nucleus
δ nucleus
ε nucleus
γ mitochondria
β reparation
Components
• ORI: located in the middle of the fork (bubble). Recognized by union proteins.
• Replication fork: place where replication takes place (the bubble).
• Okazaki fragments: little pieces in discontinuous strand.
• DNA ligase: responsable of the union of okazaki fragments.
• Helicase: unwraping of the mother DNA, breaks down hidrogen bridges between the bases.
• Primase: catalyzes formation of primers.• SSDBP: Helps the DNA stabilization in a sigle
strand.• Topoisomerases: enzymes that split down
the DNA.• RNAse H: Split down DNA primers.
• PACE 1: -Recognizing ORI by
helicases. -Formation of the
fork(bubble).• PACE 2:-Manteining the fork.-SSDBP binds to the
nucleotids of the strand .
• PACE 3:- Synthesis of the
primer.- RNAse H splits the RNA
primer- Spaces filled by Pol δ,
and fragments are binded by the DNA ligase.
• PACE 4:-Replication iniciates.
• PACE 5:-Topoisomerases relaxes DNA wrappings.
• PACE 6:-Replacation process is finished. Check out the
graphic
REPLICATION FORK
• Complex of numerous proteins, one of them called CMG, which unwinds and separates DNA into two individual strands.
• The two strands of double-stranded DNA are complementary, they fit together head to tail (the 5' end to the 3' end), so that the head of one strand is attached to the tail of the other.
• This leads to a traffic problem, where the two daughter strands are created at different paces, resulting in a leading strand (Pol ε) and a lagging strand (Pol δ) are being synthesized in opposite directions (5’-3’ 3’-5’ respectively).
• Pol ε, does not attach very well to the DNA on its own. It requires the presence of the CMG to attach securely. Even in an excess of Pol δ, CMG chose Pol ε. Pol δ, however, binds very strongly to an accessory protein, the PCNA clamp, a ring shaped protein that encircles DNA. Only when the PCNA clamp is on the lagging strand does Pol δ strongly bind to PCNA.
OPINION
I my opinion this discovery is a big step in medicine and in science. Just being able to understand a little bit of how our DNA works is greatful to everyone.If every discovery is useful to fix processes, many diseases could be cured, and many people would improve their quality of life.
SWEET GENES: NEW WAY FOUND BY WHICH METABOLISM IS LINKED TO THE REGULATION OF DNAJULY 3, 2014– UNIVERSITY OF ALBERTA FACULTY OF MEDICINE AND DENTISTRY
Histones are proteins that prevents the expression of genes and the replication of DNA, which are required for cell growth and division, acting as spools around which DNA winds, creating nucleosomes.
Epigenetic regulation of DNAIs the process by which an Acetyl CoA group is donated to the Histones, so they become acetylated. This acetylation relaxes the DNA, allowing for DNA replication and gene expression.It was known that the enzyme that catalyze this process, Pyruvate Dehydrogenase Complex, resided only within the mitochondria, but now we know they discovered that it residedin the nucleus too.
Histone Acetylation
PDC
Generates Acetyl CoA
Mitochondria
Nucleus
Uses carbohydrates from our diet
Energy production
Histone Acetylation
In my opinion this finding could help scientists and doctors understand how a disease works, how fast it grow, and how can we treat it. This is great because we are in the “era” where everyone is getting sick, so they could save many lives.
MEDICAL UTILITYMEDICAL UTILITYCells have DNA, they need it in order to divide and grow. Humans are made of cells, DNA keeps development and reproduction available for us.If DNA get damaged, it would replicate that way, so when cell divides, it would have a damaged copy of DNA. This is how starts a disease.
MEDICAL UTILITYMEDICAL UTILITY
This findings would help understand diseases. For example with the replication fork, it was understood a little bit of how those enzymes do their work, and discovering PDC in the nucleus, can help us see a little more of how DNA get damaged and replicates that way.
If doctors and scientists could stop that, or fix that, people wouldn’t get sick, or maybe we can start getting cures for some diseases like cancer and heart failure.Its obviously we have genes that afects our genetics and determine our physiologic and pathologic conditions, but this discoveries, even if they seem small, they aren’t. If we could fix a disease just before it starts, it would be the sensation.
MEDICAL UTILITYMEDICAL UTILITY
With PDC in the nucleus, cancer cells grow faster. Scientists could create a drug that may regulate histone acetylation in both mitochondria and nucleus, or a drug that slows down the translocation of the PDC from the mitochondria to the nucleus. This might give time to the pacients and to the doctors to start an effective treatment that would stop cancer and metastasis.
MEDICAL UTILITYMEDICAL UTILITY• This findings have many
medical uilities, but most of all it gives us faith and determination to keep looking for the source of every disease.
• If we get to control genetic and DNA that are the basis of everything, we can control the world, because is us against diseases.
• It would help industry of nanotechnology.
BIBLIOGRAPHY• MARTÍNEZ SÁNCHEZ, Lina María, Biología Molecular, Séptima edición,
Medellín, 2012, págs. 74-84.• http://books.google.com.co/books?
id=bgQ_xyJYkigC&pg=PA50&dq=DNA&hl=es-419&sa=X&ei=hUjeU9K1O_XfsASd7YCYCA&ved=0CE4Q6AEwBg#v=onepage&q=DNA&f=false (accesed August 1, 2014)
• DNA ‘replication fork’ reconstituded for the first time http://www.sciencedaily.com/releases/2014/07/140709100106.htm (accessed July 22, 2014)
• Sweet genes: new way found by which metabolism is linked to the regulation of DNA http://www.sciencedaily.com/releases/2014/07/140703151821.htm (accessed July 20, 2014)
• http://books.google.com.co/books?id=sDQYRWEhVroC&pg=PA82&dq=histonas&hl=es-419&sa=X&ei=UEneU9LrCu-_sQSis4LIDA&ved=0CCEQ6AEwAQ#v=onepage&q=histonas&f=false (accesed July 30, 2014)