Four-Stranded DNA

The double helix DNA structure has been known to hold the chemical code for all life. Recent studies have found that this is not entirely true. Scientist have found four-stranded DNA in human cells. High concentration of quadruplexes have been linked with DNA replication errors such as cancer. Scientist have found a way to stop the quadruplexes from dividing. Therefore, this may be an exciting new way to prevent cancer cells from spreading. However, the four-strand helix is still new information. Scientist are not sure if the quadruplexes have a purpose or if it’s made completely by accident. We still need to do a lot more experiments before anyone can consider using this information to help cancer patients.

The double helix DNA has been engraved into my head so badly that I didn’t even consider that there may be variations to DNA structure. If the quadruplexes do play a big role in cancer development, we may have just discovered a way to attack tumors at their root. We may be years away before we can use this information to our advantage. Also, I don’t believe this may be the final step in curing cancer, but I do think that this may be one more step in the right direction.

G-quadruplexes - that binds the same type of protein in plants and animals

It was discovered by scientist that a type of protein executes the same job for animals and plants to connect the G-quadruplexes. This discovery can open the doors to the study of how genes in plants execute their work and also how plants are able to adapt through physical changes such as climate impacts, like flooding caused by rain and because they are unable to escape from this forms of adversities they must learn to adapt. This protein also known as the nucleoside diphosphate kinase1 (ZmNDPK1), can carry out many cellular functions and with the comprehension of their G4-binding it will allow to better understand gene regulation. These scientists are trying to discover what does the ZmNDPK1 regulates, because they use as an example that this protein can regulate the human genes that are related to the heart. After the discovery of the connection of plants and animals regarding how the same protein works in order to connect to the G4 DNA, the next step for the scientist is “to compare the functional importance of G4 DNA as conserved genetic regulatory elements” (Stroupe ) as quoted by Stroupe.

3-D Changes in DNA May Lead to a Genetic Form of Lou Gehrig's Disease

A new discovery by Jiou Wang, Ph.D., and his colleagues at Johns Hopkins University that a mutation in the C9orf72 gene can cause neurodegeneration, or altering the shape of DNA which, in turn, kills the DNA molecule. Mutations in this C9orf72 gene causes amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease), as well as frontotemporal degeneration (FTD). They also believe this mutation might be associated with Alzheimer's and Huntington's disease. In a normal C9orf72 gene, the nucleotide sequence repeats between 2-25 times, however, the mutation causes the gene to repeat tens of thousands of times. With these extra repetitions, the shape of the DNA molecules changes from the twisted ladder to G-quadruplexes (image below), which are stacks of square-shaped molecules called G-quartets. This mutation has serious effects on how the genetic message is processed. The mutated DNA forms a DNA-RNA hybrid structure called R-loops. The R-loops and G-quadruplexes disrupt the transcription process, thus patients with this mutation produce short transcripts. The cell functions abnormally because of these short transcripts. Dr. Wang also determined that this mutation effects the nucleolus which contains the cell's DNA and is the site for initial protein assembly. Dr. Wang teamed up with Jeffery D. Rothstein, M.D., also from Johns Hopkins University to observe the effects of the C9orf72 mutation on nucleolin which is a key protein inside the nucleolus. Their research show that the short transcripts bound to the nucleolin has toxic effects on the cell. In a healthy cell, the nucleolin is only present in a certain area of the nucleus, while in the cells from the ALS patients, nucleolin is present throughout the nucleus. They hypothesize that abnormal distribution of nucleolin kills the cell and results in ALS and FTD.

(The above image shows a G-quadruplex configuration)
I find this new discovery very important because now we know what happens on the molecular scale for ALS and FTD to occur. Scientist can now do experiments on how to stop this phenomenon from happening. This discovery also puts the foot in the door for a cure for Alzheimer's and Huntington's disease. This could be the start for some incredible discoveries in the future regarding ALS, FTD, Alzheimer's and Huntington's disease.