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Sasicha Manupipatpong

Identical DNA codes discovered in different plant species - 2 views

www.sciencedaily.com/...120409164426.htm

plant species identical DNA sequences medicine

shared by Sasicha Manupipatpong on 16 Apr 12 - No Cached
  • found identical sequences of DNA located at completely different places on multiple plant genomes
  • Although the scientists found identical sequences between plant species, just as they did between animals, they suggested the sequences evolved differently.
  • find identical sequences in plant DNAs
  • ...9 more annotations...
  • identical sections weren't found at the same points
  • genomes of six animals (dog, chicken, human, mouse, macaque and rat)
  • six plant species (Arabidopsis, soybean, rice, cottonwood, sorghum and grape)
  • found long strings of identical code in different species of animals' DNA
  • expect to see convergent evolution, but we don't
  • Plants and animals are both complex multi-cellular organisms that have to deal with many of the same environmental conditions, like taking in air and water and dealing with weather variations, but their genomes code for solutions to these challenges in different ways
  • could help in the development of new medicines
  • used to find identical sequential patterns in an organism's entire set of proteins
  • lead to finding new targets for existing drugs or studying these drugs' side effects
  • Sasicha Manupipatpong on 16 Apr 12
     
    A computer algorithm found identical sequences of DNA in different places of various plant species' genomes. The same has been found in animals. This could prove to be beneficial in the development of new medicines (for testing drug side effects).
wasin kusakabe

Deep sequencing reveals potentially toxic, trade-restricted ingredients in some traditi... - 1 views

www.sciencedaily.com/...120412182328.htm

DNA sequencing Toxic Traditional Chinese Medicine

shared by wasin kusakabe on 15 Apr 12 - No Cached
  • DNA sequencing technology to reveal the animal and plant composition
  • of traditional Chinese medicines
  • These plants contain chemicals that can be toxic if the wrong dosage is taken, but none of them actually listed concentrations on the packaging.”
  • ...5 more annotations...
  • estricted animals that are classified as vulnerable, endangered, or critically endangered, including the Asiatic black bear and Saiga antelope.”
  • multiple samples that contained DNA from animals listed as trade-restricted
  • mislabelling of TCMs
  • including animal DNA and potential allergens such as soy or nuts.
    • wasin kusakabe
      wasin kusakabe on 15 Apr 12
       
      Traditional Chinese Medicines have incorrect labeling, which may lead to allergic reaction or crossing religious restrictions.
  • wasin kusakabe on 15 Apr 12
     
    Traditional Chinese Medicines' ingredients revealed by DNA sequencing to be potentially toxic.
Pop karnchanapimonkul

The Ballooning Brain: Defective Genes May Explain Uncontrolled Brain Growth in Autism: ... - 0 views

www.scientificamerican.com/article.cfm

brain genes autism

shared by Pop karnchanapimonkul on 13 Apr 12 - No Cached
  • linked atypical gene activity to excessive growth in the autistic brain
  • autistic brain sprouts an excess of neurons and continues to balloon during the first five years of life, as all those extra neurons grow larger and form connections.
  • start to lose neural connections, faster than typical brains
  • ...11 more annotations...
  • 67 percent more neurons in their prefrontal cortex (PFC) than typical children
  • executive functions"—high-level thinking, such as planning ahead, inhibiting impulses and directing attention.
  • In brain tissue from both autistic children and autistic adults, genes coding for proteins that identify and repair mistakes in DNA were expressed at unusually low levels. Additionally, all autistic brains demonstrated unusual activity levels for genes that determine when neurons grow and die and how newborn neurons migrate during early development
  • Some genes involved in immune responses, cell-to-cell communication and tissue repair, however, were expressed at unusual levels in adult autistic brains, but not in autistic children's brains
  • Errors accumulate.
  • autistic child develops in the womb, something—an inherited mutation or an environmental factor like a virus, toxin or hormone—muffles the expression of genes coding for proteins that usually fix mistakes in sequences of DNA
  • The genetic systems controlling the growth of new neurons go haywire, and brain cells divide much more frequently than usual, accounting for the excess neurons found in the PFC of autistic children.
  • autistic brain grow physically larger and form more connections than in a typical child's brain.
  • immune system reacts against the brain's overzealous growth,
  • Not all researchers, however, accept
  • If scientists definitively link autism to a characteristic sequence of changes in gene expression and unusual neural growth, then it becomes possible to target and reverse any one of the thousands of steps in that sequence.
  • Pop karnchanapimonkul on 13 Apr 12
     
    Article about how genetic expression may be the cause for autism.
Sasicha Manupipatpong

Divergent evolution illuminated: Light shed on reasons behind genome differences betwee... - 0 views

www.sciencedaily.com/...120329124607.htm

trna dna evolution genome differences proteins biotechnology

shared by Sasicha Manupipatpong on 01 Apr 12 - No Cached
  • divergent evolution of the genomes of different groups of species
  • three large domains: Archaea, Bacteria and Eukarya
  • genomes of each group have evolved towards distinct structures that have favored their separation
  • ...15 more annotations...
  • connection between the function of enzymes and the composition of the genomes shed light on the evolution and structure of genes
  • analyzed the distribution and abundance of transfer RNA genes
  • structure of genomes was adapted to the activity of some enzymes, which differ for Bacteria and for Eukarya and are absent in Archaea
  • activity of these enzymes modifies tRNAs, allowing them to recognize up to three distinct codons
    • Sasicha Manupipatpong
      Sasicha Manupipatpong on 01 Apr 12
       
      Prior to the study, it was understood that tRNA's have a specific anti-codon sequence which would recognize a single mRNA codon with the complementary sequence. Does this mean that the tRNA also attaches to different amino acids as well? How does the tRNA differentiate between the different amino acids it is at that moment carrying and the codon it matches with on the mRNA--does it change shape according to which amino acid is attached to it?
  • activity of the bacterial and eukaryal enzymes is different, which explains why the genomes and the gene composition of bacteria, eukarya, and archaea have diverged
  • relation between genome structure and the speed of protein synthesis from its genes
  • demonstrates how organisms have evolved in a different manner to achieve better adaptations and to have optimum protein translation efficiency
  • biotechnology as the discovery of the relevance of these modifications will allow an improvement in the industrial production of proteins
  • another parameter with which to optimize the synthesis of proteins from a gene
  • human insulin is "manufactured" in bacteria and our discovery would allow this production to be increased if we take into account the activity of these enzymes
  • relevant for the study of cancer: "it is possible that these modification enzymes are over-represented in some kinds of cancer. In fact, this would be logical because cancer cells are highly efficient in producing proteins."
  • greater the abundance of a protein in a cell the higher the number of triplets found in its gene sequence that can be read by modified tRNAs
  • don't exactly know why these enzymes appear or why they are different in bacteria and in eukaryotes but it's clear that they contribute to the separation of genomes of these two groups
  • genetic code is the same
  • what has changed is the relative importance of different codons of the code
  • Sasicha Manupipatpong on 01 Apr 12
     
    A recent study uncovers the reasons for the divergent evolution of the genomes of different species. The findings provide information about tRNA modifications which may prove useful in the field of biotechnology, specifically in the industrial production of proteins
wasin kusakabe

Athletic frogs have faster-changing genomes - 0 views

www.sciencedaily.com/...120412182332.htm

DNA Genomes Athletic Frogs

shared by wasin kusakabe on 14 Apr 12 - No Cached
    • wasin kusakabe
      wasin kusakabe on 14 Apr 12
       
      Physical activities can change the DNA sequence which can be passed on to later generations. However this has only been tested on frogs and may not apply to mammals like us.
  • athletic frogs tended to have faster-changing genomes.
  • Stretches of DNA accumulate changes over time
  • ...3 more annotations...
  • Physically fit frogs have faster-changing genomes
  • During exercise, the circulatory system provides blood and oxygen to the tissues that are needed most
  • When physical activity has stopped, the rush of blood and oxygen when circulation is restored to those tissues produces a burst of free radicals that can cause wear and tear on DNA, eventually causing genetic changes that -- if they affect the DNA of cells that make eggs or sperm -- can be passed to future generations.
Kantham Hongdusit

Improved Understanding Of Cancer Progression - 0 views

www.medicalnewstoday.com/...244086.php

shared by Kantham Hongdusit on 15 Apr 12 - No Cached
  • Kantham Hongdusit on 15 Apr 12
     
    Researchers in IMIM have discovered the function of the enzyme LOXL2, which is one of the factor causing cancer. The enzyme interacts with histone H3, and changes the DNA sequence around that histone, eliminating the lysine 4 amino acid group, which favors tumor development
nidthamsirisup

Epigenetics: DNA Isn't Everything - 0 views

www.sciencedaily.com/...090412081315.htm

epigenetics genetics gene

shared by nidthamsirisup on 15 Apr 12 - Cached
  • Research into epigenetics has shown that environmental factors affect characteristics of organisms. These changes are sometimes passed on to the offspring.
  • A certain laboratory strain of the fruit fly Drosophila melanogaster has white eyes. If the surrounding temperature of the embryos, which are normally nurtured at 25 degrees Celsius, is briefly raised to 37 degrees Celsius, the flies later hatch with red eyes.
  • crossed the flies for six generations. In this experiment, they were able to prove that the temperature treatment changes the eye colour of this specific strain of fly, and that the treated individual flies pass on the change to their offspring over several generations. However, the DNA sequence for the gene responsible for eye colour was proven to remain the same for white-eyed parents and red-eyed offspring.
  • ...7 more annotations...
  • Epigenetics examines the inheritance of characteristics that are not set out in the DNA sequence.
  • important factors are the histones, a kind of packaging material for the DNA, in order to store DNA in an ordered and space-saving way. It is now clear that these proteins have additional roles to play. Depending on the chemical group they carry, if they are acetylated or methylated, they permanently activate or deactivate genes.
  • New methods now allow researchers to sometimes directly show which genes have been activated or deactivated by the histones
  • The genetic information of the DNA is passed on along with the relevant epigenetic information for the respective cell type.
  • A similar question remains for the inheritance of the epigenetic characteristics from parents to offspring. They now know that when the gametes are formed, certain epigenetic markers remain and are passed on to the offspring. The questions, which are currently being researched, are how much and which part of the epigenetic information is preserved and subsequently inherited.
  • Diet and epigenetics appear to be closely linked. The most well known example is that of the Agouti mice: they are yellow, fat and are prone to diabetes and cancer. If Agouti females are fed with a cocktail of vitamin B12, folic acid and cholin, directly prior to and during pregnancy, they give birth to mainly brown, slim and healthy offspring. They in turn mainly have offspring similar to themselves.
  • Environmental factors, which change the characteristics of an individual and are then passed on to its offspring, do not really fit into Darwin’s theory of evolution. According to his theory, evolution is the result of the population and not the single individual. “Passing on the gained characteristics fits more to Lamarck’s theory of evolution”, says Paro.
Paige Prescott

DNA The Code of Life | The Language of Life | deCODEme - 4 views

www.decodeme.com/genetic-code

dna

shared by Paige Prescott on 25 Mar 12 - No Cached
  • Genes are especially important segments of DNA that directly influence one or more traits. They are relatively small segments of chromosomes, where the sequence of DNA nucleotides encodes a recipe for making a protein. Small differences in the sequence of DNA nucleotides of a particular gene can lead to differences in the structure and behavior of the proteins they encode. It is these differences, in turn, that account for the variable characteristics of the people around you.
  • Paige Prescott on 25 Mar 12
     
    deCodeMe is a private company that sells DNA technology
Sasicha Manupipatpong

DNA sequencing helps identify cancer cells for immune system attack - 1 views

www.sciencedaily.com/...120208152342.htm

shared by Sasicha Manupipatpong on 30 Mar 12 - No Cached
  • Sasicha Manupipatpong on 30 Mar 12
     
    DNA sequences from tumor cells can be used to direct the immune system to attack cancer, according to scientists. The immune system relies on an intricate network of alarm bells, targets and safety brakes to determine when and what to attack.
orasa sukmark

Junk DNA Can Revive and Cause Disease, Study Finds - NYTimes.com - 0 views

www.nytimes.com/...20gene.html

shared by orasa sukmark on 30 Mar 12 - No Cached
  • can rise from the dead like zombies
  • dead gene come back to life and cause a disease
  • a dead gene come back to life and cause a disease.
  • ...16 more annotations...
  • Some of those genes, surprised geneticists reported Thursday, can rise from the dead like zombies, waking up to cause one of the most common forms of muscular dystrophy.
    • adisa narula
      adisa narula on 30 Mar 12
       
      Do these genes revive automatically?
  • It is a dominant genetic disease.
  • people who have the disease cannot smile.
  • FSHD affects about 1 in 20,000 people
  • function, if any, is largely unknown.
  • function, if any, is largely unknown
  • FSHD, is one of the most common forms of muscular dystrophy.
  • in a way FSHD was the easy case — it is a disease that affects every single person who inherits the genetic defect. Other diseases are more subtle, affecting some people more than others, causing a range of symptoms.
  • The dead gene was also repeated on chromosome 10, but that area of repeats seemed innocuous, unrelated to the disease. Only chromosome 4 was a problem.
  • chromosome 4 was a problem.
  • No one whose dead gene was repeated more than 10 times ever got FSHD
  • it was not completely inactive. It is always transcribed
  • copied by the cell as a first step to making a protein.
  • But the transcriptions were faulty, disintegrating right away. They were missing a crucial section, called a poly (A) sequence, needed to stabilize them.
  • But the transcriptions were faulty, disintegrating right away. They were missing a crucial section, called a poly (A) sequence, needed to stabilize them.
  • extra copies change the chromosome’s structure, shutting off the whole region so it cannot be used.
Nitchakan Chaiprukmalakan

Biotechdaily - Human Mitochondrial Mutations Repaired by New Technique - 2 views

www.biotechdaily.com/...repaired_by_new_technique.html

shared by Nitchakan Chaiprukmalakan on 01 Apr 12 - No Cached
  • researchers have identified a generic approach to correct mutations in human mitochondrial DNA by targeting corrective RNAs,
  • In adults, many aging disorders have been associated with defects of mitochondrial function, including diabetes, Parkinson’s disease, cancer, heart disease, stroke, and Alzheimer’s disease.
  • The introduction of nucleus-encoded small RNAs into mitochondria is critical for the replication, transcription, and translation of the mitochondrial genome,
  • ...4 more annotations...
  • The study defined a new role for a protein called polynucleotide phosphorylase (PNPASE) in regulating the import of RNA into mitochondria. Reducing the expression--or output--of PNPASE decreased RNA import, which impaired the processing of mitochondrial genome-encoded RNAs. Reduced RNA processing inhibited the translation of proteins required to maintain the mitochondrial electron transport chain that consumes oxygen during cell respiration to produce energy. With reduced PNPASE, unprocessed mitochondrial-encoded RNAs accumulated, protein translation was inhibited, and energy production was compromised, leading to stalled cell growth.
  • Geng Wang developed a strategy to target and import specific RNA molecules encoded in the nucleus into the mitochondria and, once there, to express proteins needed to repair mitochondrial gene mutations.
  • First, the researchers had to find a way to stabilize the reparative RNA so that it was moved out of the nucleus and then localized to the mitochondrial outer membrane. This was accomplished by modifying an export sequence to direct the RNA to the mitochondrion. Once the RNA was in the area of the transport machinery on the mitochondrial surface, then a second transport sequence was required to direct the RNA into the targeted organelle. With these two modifications, a wide range of RNAs were targeted to and imported into the mitochondria, where they worked to repair defects in mitochondrial respiration and energy production in two different cell line models of human mitochondrial disease.
    • Nitchakan Chaiprukmalakan
      Nitchakan Chaiprukmalakan on 03 Apr 12
       
      This article shows the importance of the RNAs in making proteins for the mitochondria to work efficiently.  The article summarizes a method in repairing the mitochondria that is still being worked on.
  • wasin kusakabe on 01 Apr 12
     
    Mutations in the mitochondrial genome inflicts diseases
Kaoko Miyazaki

The Rinn Lab - 0 views

www.rinnlab.com/research.html

RNA

shared by Kaoko Miyazaki on 11 Apr 12 - No Cached
  • Kaoko Miyazaki on 11 Apr 12
     
    John Rinn (RNA researcher at Harvard Medical School) continues on his ongoing research about Long Intergenic Noncoding RNA's (lincRNAs). lincRNAs used to be overlooked and classified as 'waste' products, but today it is seen as the contractors that create the DNA's coding sequence needed for the organism's structure. In simpler terms, lincRNAs are responsible for putting molecular materials in places they are supposed to be - as though following a rough draft to make a final master piece. Because lincRNAs have so many functions, if step goes wrong, it could cause potential harm to the organism such as creating a tumor. But because of their many functions like guiding the interactions of protein DNA to name one, John Rinn and other current scientists hypothesize that lincRNAs are what differentiates us from other organisms and makes us, us.
Changul Louis Yeum

Study Says DNA's Power to Predict Illness Is Limited - 0 views

www.nytimes.com/...ct-is-limited-study-finds.html

DNA disease research gene

shared by Changul Louis Yeum on 11 Apr 12 - No Cached
  • Changul Louis Yeum on 11 Apr 12
     
    The answer, according to a new study of twins, is, for the most part, "no." While sequencing the entire DNA of individuals is proving fantastically useful in understanding diseases and finding new treatments, it is not a method that will, for the most part, predict a person's medical future.
Nitchakan Chaiprukmalakan

Hoogsteen base pairs: An alternate structure in DNA - 0 views

scitechstory.com/...-an-alternate-structure-in-dna

shared by Nitchakan Chaiprukmalakan on 13 Apr 12 - No Cached
  • This discovery, made by a team of researchers from the University of Michigan (USA) and the University of California, Irvine (USA) and published in the journal Nature January 26, 2011 [Transient Hoogsteen base pairs in canonical duplex DNA] involves a new capability of nuclear magnetic resonance (NMR) machines and something most people have never heard of (including me): Hoogsteen base pairs.
  • It was discovered by the biologist Karst Hoogsteen in 1963. In effect, the Hoogsteen base pair is a ‘normal’ Watson-Crick base pair (usually A-T) flipped-over like an upside-down step on a ladder.
  • It changes the geometry and allows for truly exotic formations such as a triple helix or even quadruplex structures.
  • ...4 more annotations...
  • Hoogsteen base pairs were known to exist primarily in RNA and had been observed in DNA only when there was damage to the DNA structure, or something else like a protein or drug was bound to it.
  • In RNA the Hoogsteen base pairs have been studied fairly extensively. They are considered an “excited state” and are useful to observe unusual protein binding. In DNA the Hoogsteen base pairing, which by the way has two forms, normal and reverse, was considered an anomaly.
  • It was discovered that normal DNA undergoes these shifts about 1% of the time and they last only milliseconds.
  • “Together, these data suggest that there are multiple layers of information stored in the genetic code.” Because critical interactions between DNA and proteins are thought to be directed by both the sequence of bases and the flexing of the DNA molecule, these excited states represent a whole new level of information contained in the genetic code.
Nickyz P.

It's Alive! Artificial Life Springs From Manmade DNA : Discovery News - 0 views

news.discovery.com/...synthetic-genome-life.html

shared by Nickyz P. on 16 Apr 12 - No Cached
  • "This is the first synthetic cell that's been made," said Venter. "We call it synthetic because the cell is totally derived from a synthetic chromosome, made with four bottles of chemicals on a chemical synthesizer, starting with information in a computer."
  • Venter and his colleagues created a special code, similar to Morse code, to "write" within the DNA itself. Instead of dots and dashes, they used the sequence of four DNA nucleotides, thymine (T), guanine (G), cytosine (C), and adenine (A), as a code for any letter, number or punctuation mark. Using the code, the team included the names of the study co-authors, a website, and even several philosophical quotes, complete with punctuation.
pet-chompoo sa-ngarmangkang

Heart Failure Gene Discovered...In the Kidney - St. Louis News - Daily RFT - 0 views

blogs.riverfronttimes.com/...ure_gene_prevention_kidney.php

shared by pet-chompoo sa-ngarmangkang on 07 Apr 12 - No Cached
  • risk for heart failure
  • e high blood pressure
  • t's related to the kidney.
  • ...8 more annotations...
  • "It also makes hormones involved in maintaining blood volume."
  • So they began sequencing the kidney gene, looking for problems.
  • "The CLCNKA polymorphism decreases the kidney's functionality by about half,"
  • gene remains silent with no effect on the body until there's an injury to the heart
  • the blood flow to the kidney decreases and the kidney secretes the hormones angiotensin and aldosterone which lead to a high risk of heart failure."
  • More blood with less space to move leads to high blood pressure
  • puts more pressure on the heart.
  • presence of the gene drives the risk of heart failure from 20 percent to 27 percent for people with one copy and 54 percent for people with two
Sasicha Manupipatpong

New genes linked to brain size, intelligence - 2 views

www.sciencedaily.com/...120415150123.htm

genes linked brain size intelligence

shared by Sasicha Manupipatpong on 16 Apr 12 - No Cached
  • genes that increase your risk for a single disease that your children can inherit
  • factors that cause tissue atrophy and reduce brain size, which is a biological marker for hereditary disorders
  • schizophrenia, bipolar disorder, depression, Alzheimer’s disease and dementia
  • ...13 more annotations...
  • sample large enough to reveal clear patterns in genetic variation and show how these changes physically alter the brain
  • screened the genomes of people suffering from a specific brain disease and combed their DNA to uncover a common variant.
  • gene variants that deplete brain tissue beyond normal in a healthy person
  • unearth new genetic variants in people who have bigger brains as well as differences in regions critical to learning and memory
  • smaller brains
  • variations in their DNA that help boost or lower their brains’ susceptibility to a vast range of diseases
  • consistent relationship between subtle shifts in the genetic code and diminished memory centers
  • People also can take preventive steps through exercise, diet and mental stimulation to erase the effects of a bad gene
  • Once we identify the gene, we can target it with a drug to reduce the risk of disease
  • genes that explain individual differences in intelligence
  • People whose HMGA2 gene held a letter “C” instead of “T” on that location of the gene possessed larger brains and scored more highly on standardized IQ tests
  • gene called HMGA2 affected brain size as well as a person’s intelligence
  • About ScienceDaily®  |  Editorial Staff  |  Awards & Reviews  |  Contribute News  |  Advertise With Us  |  Privacy Policy  |  Terms of Use
  • Sasicha Manupipatpong on 16 Apr 12
     
    Specific genes have been identified which affect brain size and intelligence--a difference of one nucleotide in the DNA sequence could determine how well you score on a standardized IQ test.
Sea Maskulrath

Changes in gene expression causes high BP in pregnancy - 1 views

zeenews.india.com/...igh-bp-in-pregnancy_16515.html

epigenetics DNA human

shared by Sea Maskulrath on 16 Apr 12 - No Cached
  • Washington: Researchers have discovered that changes in the gene expression of a key enzyme may contribute to high blood pressure and increase susceptibility to forming blood clots in pregnant women with preeclampsia.
  • Epigenetics refers to changes in gene expression that are mediated through mechanisms other than changes in the DNA sequence.
  • The VCU team reported that thromboxane synthase – an important inflammatory enzyme – is increased in the blood vessels of expectant mothers with preeclampsia.The thromboxane synthase gene codes for this enzyme, which is involved in several processes including cardiovascular disease and stroke. This enzyme results in the synthesis of thromboxane, which increases blood pressure and causes blood clots.
  • ...5 more annotations...
  • According to Walsh, one of the main epigenetic mechanisms is methylation of the DNA, which controls the expression of genes. The increase of
  • his enzyme in the blood vessels is related to reduced DNA methylation and the infiltration of neu
  • enzyme
  • trophils
  • trophils into the blood vessels. Neutrophils are white blood cells that normally help fight infection.
chanon chiarnpattanodom

Cancer epigenetics takes center stage - 1 views

www.pnas.org/...392.full

shared by chanon chiarnpattanodom on 16 Apr 12 - No Cached
    • chanon chiarnpattanodom
      chanon chiarnpattanodom on 16 Apr 12
       
      DNA methylation is a chemical process where a methyl group is added on either the cytosine ring or the adenine ring, used in "higher leveled" organisms. Important in cell differentiation since methylation will cause cells to "remember" and remain differenciated instead of expressing other genes. 
  • Epigenetics is defined as modifications of the genome, heritable during cell division, that do not involve a change in the DNA sequence.
  • Epigenetic alterations in cancer include global hypomethylation
  • ...18 more annotations...
  • the promoters of housekeeping genes that are generally protected from methylation.
  • may lead to aberrant silencing of tumor suppressor genes
  • discovered loss of imprinting (LOI) in cancer
  • Genomic imprinting, the subject of the report by Nakagawa et al. (2), is an epigenetic modification of a specific parental allele of a gene, or the chromosome on which it resides, in the gamete or zygote, leading to differential expression of the two alleles of the gene in somatic cells of the offspring.
  • we found that LOI can occur in the normal colonic mucosa of colorectal cancer patients with LOI in their tumors
  • This LOI was linked to cases showing microsatellite instability (MSI) in the tumors
  • However, these patients do not have mutations in mismatch repair genes
  • One potential cause of MSI in these sporadic cancers is hypermethylation and epigenetic silencing of the hMLH1 mismatch repair gene
  • Nakagawa et al. (2) now confirm the original study of Cui et al. that LOI occurs in both tumor and normal tissue of patients
  • The present study (2) also offers an intriguing mechanistic hypothesis to explain the relationship between H19 DMR methylation and LOI in these patients
  • Nevertheless, the study calls attention to this remarkable highly conserved multifunctional protein,
  • The potential link to CTCF suggested by this study also calls our attention to the link among DNA methylation, epigenetics, and chromatin.
  • A clue to the link between MSI and epigenetics may be provided by another sometimes overlooked common thread in epigenetics, namely DNA replication
  • repeat-induced gene silencing is thought to be propagated through hemimethylated intermediates during DNA replication
  • The studies of Cui et al. (11), Nishihara et al. (20), and Nakagawa et al. (2) suggest a new and provocative view of the timing of epigenetic changes in cancer.
  • Studies of transgenic mice with constitutive biallelic expression of IGF2, comparable to LOI, show reduced apoptosis and increased tumor formation
  • I conclude by noting that the distinction between cancer genetics and epigenetics has blurred considerably in recent years
  • Many conventional “genetic” mechanisms directly affect proteins that regulate chromatin,
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