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nidthamsirisup

Mysterious Noncoding DNA: 'Junk' or Genetic Power Player? | PBS NewsHour - 0 views

www.pbs.org/...junk-dna.html

noncoding DNA gene

shared by nidthamsirisup on 15 Apr 12 - No Cached
  • Genes represent only a tiny fraction -- 1 percent -- of our overall genetic material. Then there's the other 99 percent of our DNA -- the stuff that doesn't make protein
  • Researchers have found that some of this noncoding DNA is in fact essential to how our genes function and plays a role in how we look, how we act and the diseases that afflict us.
  • Embedded in this 99 percent is DNA responsible for the mechanics of gene behavior: regulatory DNA. Greg Wray of Duke University's Institute for Genome Sciences and Policy describes the regulatory DNA as the software for our genes, a set of instructions that tells the genome how to use the traditional coding genes.
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  • "It's like a recipe book," Wray said. "It tells you how to make the meal. You need to know the amounts. You need to know the order. The noncoding DNA tells you how much to make, when to make it and under what circumstances."
  • common diseases are probably more influenced by regulatory differences, Harismendy said. These include Type 2 diabetes, Crohn's disease, Alzheimer's Disease and a variety of cancers, including breast, colon, ovarian, prostate and lung.
  • According to Wray, research has shown that diseases like bipolar syndrome and clinical depression may be associated with noncoding mutations that determine whether the brain is producing too much or not enough of a particular neurotransmitter. One noncoding mutation gives a person almost complete protection against the nasty malaria parasite, plasmodium vivax.
  • Another piece of noncoding DNA regulates the enzyme responsible for lactose tolerance, the ability to digest milk. Research by Wray and other scientists has shown that in four populations where dairy consumption is a vital part of the diet, new mutations have appeared that essentially keep the gene that produces the lactase enzyme from switching off.
  • And recent research done by evolutionary biologists suggests that differences in regulatory DNA may represent a major part of what separates us from chimpanzees.
Nitchakan Chaiprukmalakan

Missing Lincs - Science News - 6 views

www.sciencenews.org/...Missing_Lincs

shared by Nitchakan Chaiprukmalakan on 25 Mar 12 - No Cached
    • Nitchakan Chaiprukmalakan
      Nitchakan Chaiprukmalakan on 01 Apr 12
       
      Scientists are finding more information about the importance of the non coding RNAs, lincRNAs.
  • Only now have scientists begun identifying the previously invisible contractors who make sure that materials get where they are supposed to be and in the right order to build a human being or any other creature. Some of these little-known workers belong to a class of molecules called long intergenic noncoding RNAs.
  • And the lincRNAs originate in what scientists used to view as barren wastelands between protein-coding genes. But new research is showing that these formerly underappreciated workers have important roles in projects both large and microscopic.
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  • In the last few years, scientists have learned that lincRNAs, as well as other RNAs that are long and noncoding but not intergenic, perform a variety of jobs. Some serve as guides showing proteins where to go, while others tether proteins to different types of RNA, or to DNA. Some work as decoys, distracting regulatory molecules from their usual assignments. Some may even have multiple roles, all the while chattering away to other RNA within cells. (It is not idle gossip; RNA communication within cells may ward off diseases such as cancer.) And as the ultimate multitaskers, lincRNAs keep proper cellular development ticking along and help define what makes mice mice and people people.
  • That archive contains about 3 billion genetic letters, far more than the genomes of less complex organisms such as roundworms and fruit flies.
  • In 2005, the research revealed that even though genes that code for proteins make up only 1.5 percent of the mouse genome, more than 63 percent of the genome’s DNA is copied into RNA. In humans the number is even higher, with up to 93 percent of the genome made into RNA, even though protein-coding genes make up less than 2 percent of the genome.
  • At first, many scientists didn’t know what to make of the excess RNA. Some thought it was overexuberance on the part of the DNA-copying machinery. But gradually researchers began to realize that many of those extra RNAs had important jobs to do.
  • Some, though, appear to act like general contractors — not hammering in the nails and pouring the foundations of cells themselves, but dictating how the job should be done.
  • One of the most famous long noncoding RNAs, known as XIST, is also one of the most hands-on. XIST is in charge of shutting down one of the X chromosomes in every single cell of women and girls
  • XIST doesn’t have a long commute to work; it coats whichever X chromosome makes it, preventing other genes on the chromosome from being activated
  • One of the most well-studied linc­RNAs, named HOTAIR, wasn’t lucky enough to get a job close to home. It is copied from DNA on chromosome 12 but has to travel to chromosome 2 to shut down several genes in a group known as the HOXD cluster, genes important for proper development of an organism
  • Not only does HOTAIR help direct development, but it is also important throughout life to help cells pinpoint their location in the body.
  • Whether promoting health or mis­directing cells, lincRNAs don’t necessarily act alone.
  • A lincRNA known as HOTTIP also works with a crew of histone modifiers, but instead of shuttering genes, HOTTIP’s crews hang grand-opening signs to attract gene-activating machinery
  • In the recipe for humans, lincRNAs are in the thick of things from the very beginning. At least 26 different lincRNAs need to be on to keep an embryonic stem cell a stem cell
  • Just how lincRNAs choose which genes to turn on and off isn’t yet known. But Pier Paolo Pandolfi, a geneticist at Beth Israel Deaconess and Harvard Medical School, suspects that the lincRNAs are whispering to each other and to other RNAs, keeping tabs on all a cell’s goings-on. Pandolfi laid out his hypothesis for how this chatter might help control protein production and other processes in the Aug. 5 Cell.
  • The Columbia team and Pandolfi’s team independently found that tweaking levels of a few messenger RNAs that distract microRNAs from PTEN messenger RNA can lead to prostate cancer or a type of brain tumor called glioblastoma. Just messing with levels of a messenger RNA from another gene known as ZEB2 throws off PTEN protein levels and can lead to melanoma in mice, Pandolfi’s group reported in another paper in the Oct. 14 Cell.
  • Losing one noncoding RNA may be disastrous for a cell, but for want of noncoding RNAs whole species may never have evolved, argues Queensland’s Mattick. He and others say the real function of lincRNAs is to give evolution a sort of molecular clay from which to mold new designs.
  • Humans have several lincRNAs that are found in no other species. Many of those RNAs are made in the brain, leading scientists to speculate that the molecules may be at least partially responsible for that important organ’s evolution.
  • Paige Prescott on 25 Mar 12
     
    Is RNA the most important molecule in the cell? There is a lot of evidence leading to new understandings of RNA and it's role in many different mechanisms within a cell.
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.
Kaoko Miyazaki

Long Intergenic Noncoding RNAs: New Links in Cancer Progression - 1 views

cancerres.aacrjournals.org/...3.full

research gene epigenetics RNA

shared by Kaoko Miyazaki on 16 Apr 12 - No Cached
  • Kaoko Miyazaki on 16 Apr 12
     
    The newly discovered and currently being researched lincRNAs are seen to be one of the causes of cancer. The function of lincRNAs to control gene expression by regulating the number of histones according to specific chromatin, may cause cancer when done wrong or are altered in some way. The epigenetic alterations that occur when this function is done wrong may lead to the disease and the inheritance of it. Which could be hypothesized as to why people with a history of cancer (and other diseases) within their families have higher likelihood to being diagnosed with the disease. But because lincRNA is a very recent discovery and only less than 1% of it has has been characterized in the human body, evidence of this is still being researched, tested and studied.
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