Monday, January 21, 2013

Scientists find entirely new DNA structure

All life forms on earth are based on DNA, the building blocks that hold the information that cells need to produce the necessary proteins to keep themselves alive and functional. In 1953, scientists finally elucidated the structure of the DNA, that became henceforth known as the double helix structure. Basically, it looks like two spiralling and entwining staircases that are made up of four different building blocks. All DNA that we know pretty much looks like a double helix, but now it appears that there may also be something now known as a quadruple helix. This discovery regarding a fundamental new structure of the DNA begs the question what kind of hidden information we have yet to discover in our genetic code.

According to researchers from the University of Cambridge, the institution that also discovered the original structure of DNA 60 years ago, these quadruple helixes mainly form in areas of the genome that are rich in building block 'G', also known as guanine. The other three building blocks are known as A, T and C. At those G-rich sites in the DNA, four 'wires' of genetic code entwine to form a quadruple helix, while it normally just takes two of those wires to form DNA. While such quadruples were not previously discovered in live cells, they were already hypothesized based on computerized models.
Left: the quadruple helix structure. Right: the illuminated pieces represent DNA structures with a quadruple helix.
It appears as if those quadruple helices are mainly involved with copying DNA. Apparently, the four-stranded pieces of code incite the cell to copy its genome and consequently proceed with the process of cell division. If this gets out of control, cell division can lead to increased growth of tissues, one of the main features of tumours. That is why the scientists think that blocking the quadruple helix structures with special molecules may be a novel therapeutic target in the battle against cancer.

Preliminary research already showed that blocking the quadruple helices leads to an arrest in DNA replication and cessation of cell division. While this does not necessarily guarantee their function as a novel effective treatment, it does reveal a clear-cut relationship with the underlying process that tumours cells need to maintain themselves. The next step will therefore be to find out whether quadruple helix DNA can be targeted in cancer patients.

Watson and Crick
In 1953, two British scientists working at the University of Cambridge were the first ones to fully elucidate the structure of the genetic code. Many more scientists had been working on this topic, as revealing the structure was thought to aid in our understanding DNA's capability to store and pass on information. Those two British scientists were Watson and Crick, and both gentlemen received the Nobel prize of Physiology in 1962 for their work.
The double helix structure of DNA with its four building blocks.

1 comment:

  1. PLEASE help and as soon as someone can. I need to know (I'm not very good with the abstract or very bright.) the order of 'things'. Is it a cell, within the cell, there is a nucleus, within the nucleus, there are molecules, that make DNA which is made of chromosomes, that carry genes? I'm trying to find a simplified order or 'make up', if you will that is so generic and simple, I can basically, read it off to 3rd graders at my church tomorrow night. Is there anyone out there who will help me get this straight in my feeble brain, please. I will really appreciate any assistance. Thanking you in advance.