New instruction manual discovered for repairing broken DNA

_{Denyse O'Leary

June 29, 2017

Cell biology, Design inference}

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yeast colonis surviving DNA breakage/Georgia Tech

Drexel University and Georgia Institute of Technology researchers have discovered how the Rad52 protein is a crucial player in RNA-dependent DNA repair. The results of their study, published in Molecular Cell, reveal a surprising function of the homologous recombination protein Rad52. They also may help to identify new therapeutic targets for cancer treatment.

Radiation and chemotherapy can cause a DNA double-strand break, one of the most harmful types of DNA damage. The process of homologous recombination — which involves the exchange of genetic information between two DNA molecules — plays an important role in DNA repair, but certain gene mutations can destabilize a genome. For example, mutations in the tumor suppressor BRCA2, which is involved in DNA repair by homologous recombination, can cause the deadliest form of breast and ovarian cancer. Paper. (paywall) – Olga M. Mazina, Havva Keskin, Kritika Hanamshet, Francesca Storici, Alexander V. Mazin. Rad52 Inverse Strand Exchange Drives RNA-Templated DNA Double-Strand Break Repair. Molecular Cell, 2017; DOI: 10.1016/j.molcel.2017.05.019 More.

Darwinism is beyond ridiculous and the only solution now is retirements.

See also: Haldane’s Dilemma is still really a dilemma

Comments

EA @1:
We’re barely starting to scratch the surface. The very fact that organisms have any ability to repair at all, from the DNA right on up to organs, is an astonishing engineering feat. At the DNA level, add “repair” as a very significant requirement to the long list of known biological functions, the sources of which have not yet been pinned down. We are barely starting to get an inkling of the amount of complex functional specified information that has been loaded into living organisms.
Exactly. We ain't see nothin' yet. The most fascinating discoveries are still ahead.Dionisio_{July 1, 2017
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New instruction manual discovered for repairing broken DNA In other words, mindless processes evolved mindless proactivity... It makes perfect sense now...What was I thinking?J-Mac_{June 30, 2017
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DNA and RNA error checking and repair, amazing evidence of design http://reasonandscience.heavenforum.org/t2043-dna-and-rna-error-checking-and-repair-amazing-evidence-of-design Jon Lieff MD: http://jonlieffmd.com/blog/dna-proofreading-correcting-mutations-during-replication-cellullar-self-directed-engineering During replication, nucleotides, which compose DNA, are copied. When E coli makes a copy of its DNA, it makes approximately one mistake for every billion new nucleotides. It can copy about 2000 letters per second, finishing the entire replication process in less than an hour. Compared to human engineering, this error rate is amazingly low. E coli makes so few errors because DNA is proofread in multiple ways. An enzyme, DNA polymerase, moves along the DNA strands to start copying the code from each strand of DNA. This process has an error rate of about one in 100,000: rather high. When an error occurs, though, DNA polymerase senses the irregularity as a distortion of the new DNA’s structure, and stops what it is doing. How a protein can sense this is not clear. Other molecules then come to fix the mistake, removing the mistaken nucleotide base and replacing it with the correct one. After correction, the polymerase proceeds. This correction mechanism increases the accuracy 100 to 1000 times. A Second Round of Proofreading There are still some errors, however, that escape the previous mechanism. For those, three other complex proteins go over the newly copied DNA sequence. The first protein, called MutS (for mutator), senses a distortion in the helix shape of the new DNA and binds to the region with the mistaken nucleotides. The second protein, MutL, senses that its brother S is attached and brings a third protein over and attaches the two. The third molecule actually cuts the mistake on both sides. The three proteins then tag the incorrect section with a methyl group. Meanwhile, another partial strand of DNA is being created for the region in question, and another set of proteins cut out the exact amount of DNA needed to fill the gap. With both the mistaken piece and newly minted correct piece present, yet another protein determines which is the correct one by way of the methyl tag. That is, the correct one does not have the methyl tag on it. This new, correct section is then brought over and added to the original DNA strand. This second proofreading is itself 99% efficient and increases the overall accuracy of replication by another 100 times.Otangelo Grasso_{June 30, 2017
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Great stuff. We're barely starting to scratch the surface. The very fact that organisms have any ability to repair at all, from the DNA right on up to organs, is an astonishing engineering feat. At the DNA level, add "repair" as a very significant requirement to the long list of known biological functions, the sources of which have not yet been pinned down. We are barely starting to get an inkling of the amount of complex functional specified information that has been loaded into living organisms.Eric Anderson_{June 29, 2017
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