Double Strand Break

Words: 1425
Pages: 6
Open Document
There are an estimated 1.6 million new cancer cases anticipated in the United States in 2014, with breast cancer in women accounting for approximately 232,000 of those cases (5). More than half a million people in the United States alone will die this year from cancer (6). To date there are more than 100 known cancers from most every tissue in the body. The development of cancer within the body stems from a cellular malfunction that leads to disruption of cell cycle control. This lack of control may originate from an alteration of mitosis leading to rapid cell division or from prevention of senescence or apoptosis. Regardless of the final fate, the initial perturbation is introduced at the molecular level through genetic alterations. …show more content…
In this case, the process of homologous recombination is necessary to utilize the other gene copy as a template to fill the gap created by the break. There are a significant number of proteins utilized in the repair of a double stranded break as illustrated in Figure 1 (1). This pathway is ultimately regulated by Ataxia telangiectasia mutated (ATM) a serine/threonine protein kinase. Following the identification of a DNA double strand break, ATM is recruited and activated to begin phosphorylation of a number of other proteins involved in damage repair. The effects on cell cycle regulation as a result of the inability to repair DNA double stranded breaks have been shown to be involved in cancers such as breast cancer. The genes breast cancer 1, early onset (BRCA1) and breast cancer 2, early onset (BRCA2) are known to be part of the cell cycle check point regulation in response to DNA double strand breaks.

The BRCA1 and BRCA2 genes encode for the BRCA1 and BRCA2 tumor suppressor proteins, respectively. These proteins play roles cell cycle control and DNA double strand repair through the completion of homologous recombination. As illustrated in Figure 2, BRCA1 and BRCA2 proteins are expressed from the G1 through M phases of the cell cycle. The levels of protein are gradually increased to allow for proper regulation of DNA breaks and other cell cycle checkpoints. With improper interactions …show more content…
In the case of a trauma resulting in a DNA double strand break, ATM phosphorylates ataxia telangiectasia and Rad3-related protein (ATR). ATR is a serine/threonine protein kinase that phosphorylates the hydroxyl group on serines and threonines and in the case of double strand breaks, is responsible for phosphorylation of BRCA1. The phosphorylated BRCA1 is then responsible for recruiting a variety of other tumor suppressor proteins to the site of the double stranded break. BRCA1 will bind to the DNA holding the other proteins in place to repair the break. This action also causes a cascading effect that allows for cell cycle check point regulation to prevent the cell from progressing through the cycle until the DNA is
Show More

Related Documents: Double Strand Break

Study guide Essay

(in DNA it is deoxyribose), a phosphate group and one of the nitrogen bases (A, T, G, and C). All of their parts are joint in the same way. T and C are pyrimidines (single ring structure) and A and G are purines (which are larger, bulkier molecules, double ring structure). Rosalind Franklin had obtained especially good x- ray diffraction images of DNA fibers. By this process, a beam of x-rays is directed at a molecule. The molecule scatters the beam in patterns that can be captured on film. The pattern…

Words 534 - Pages 3

Excision Repair Research Paper

removed. The complete mechanism is as follows: first a large multienzyme complex scans the DNA for any damage (in the form of distortion/lesion in the double helix). Once the abnormality in the DNA is found, the multienzyme complex cleaves the phosphate backbone on both sides and completely removes the entire nucleotide. The resulting gap in the DNA strand is then repaired by DNA polymerase and DNA ligase. Translesion synthesis occurs when the damage to the DNA is too severe and regular repair mechanisms…

Words 1300 - Pages 6

The Cause Of Lung Cancer

After smoking, ionizing radiation or more specifically, radon gas is the second biggest cause of lung cancer. Radon is a naturally occurring, colorless, odorless, radioactive gas noble gas. It is the product of radioactive decay of the elements uranium, thorium, and radium in rocks and soil. Radon is present in nearly all air but in small amounts. When inhaled radon is mostly exhaled again. However, sometimes the radon atoms would decay while inside the lungs and release alpha particles and daughter…

Words 414 - Pages 2

Why Are Bacteriophages So Useful In DNA Research?

as many as hundreds of genes. Phage replicate within bacteria following the injection of their genome into the cytoplasm. 2. Why does DNA display a viscous-no viscous behavior at different temperatures? The secondary bonds of a polymer constantly break and reform due to thermal motion. Application of a stress favors some conformations over others, so the molecules of the polymer will gradually "flow" into the favored conformations over time.[11] Because thermal motion is one factor contributing to…

Words 552 - Pages 3

The Concepting Of Cells And Consequences Of DNA Symcules

the parent molecule as the hydrogen bonds between the base pairs break. SSB proteins prevent reanealing of single stranded DNA. Many molecules of SSB bind cooperatively to single stranded DNA, stabilizing separated strands and preventing renaturation. The sequence of bases on each of the separated strands serves as a template to guide the insertion of a complementary set of bases on the strand that is being synthesized. The new strands are assembled from deoxynucleoside triphosphates. Each incoming…

Words 661 - Pages 3

Essay on Latin: Dna and Amino Acids

base and the sugar are connected. The free 3’ end is where the other phosphate groups can attach to make a chain of sugar and phosphates, the backbone of the double helix structure of DNA. The DNA consists of two of these strands of continuous nucleotides which are connected by the bases pairs along the middle of the double helix. The double helix is basically the shape of a ladder twisted round as if someone were at the top and bottom of this ladder twisting in opposite directions. Since each side…

Words 1059 - Pages 5

Polymerase Chain Reaction Lab Report

temperature is necessary to break weak hydrogen bond that binds the two stands of DNA together and as a result multiple copies of a specific DNA sequence can be obtained. In order to carry out PCR successful, following components are required. Target DNA molecule, A pair of DNA primers, Heat resistant DNA polymerase, All four types of deoxynucleotide triphosphate (dNTPs) Target DNA molecule is a segment of double stranded DNA that contains the…

Words 906 - Pages 4

Essay about Ch. 04 Study Guide

Catabolism-Breakdown of large molecules; catabolic metabolism 3. A disaccharide is formed when two monosachharides (simple sugars) come together while water is removed. This is an example of a __dehydration synthesis reaction. 4. When water is added to break the disaccharide into the smaller monosachharides we call this a __hydrolysis reaction. 5. What is the relationship between an enzyme and a substrate? Explain how this relationship works. Enzymes are specific and only act on their corresponding…

Words 2416 - Pages 10

Dietary Macromolecules Essay

'How proteins in the diet are disassembled and then reassembled to form useful proteins in the body’ The human gastrointestinal tract has the complex task of breaking down dietary macromolecules such as proteins, carbohydrates and lipids. In their food form, these macromolecules are unable to be absorbed by the epithelial cells in the digestive tract so need to be deconstructed into their component parts. The production of protein is one of the bodies key metabolic processes. The journey from…

Words 1325 - Pages 6

Dna and Amino Acids Essay

instructions used in building proteins – DNA replicates and makes copies of itself to pass onto other cells – Mutates: Genetic Diversity – Replication of DNA, Transcription mRNA, Translation Protein DNA Replication 1) 2 strands of DNA become “ladder like” 2) Enzyme hilicase breaks H-Bonds and unzips – DNA is opened at “Replication origin” 3) Free floating nucleotides in the nucleoplasm move to appropriate position via complementary base pairing – The enzyme DNA polymerase facilitates base pairing…

Words 2532 - Pages 11