Telomeres: Gateway to Life

This month, two new things happened in science. On October 5, the Nobel Prize was, for the first time, given to two women, Carol Greider and Elizabeth Blackburn. The prize was also shared with Jack Szostak. The three scientists are given the award for their contributions to the discovery of telomeres and telomerase in the 1980s. These two components exist in every chromosome we have, and scientists have connected them to the length of cell life.
At the end of our chromosomes there are protective caps called telomeres. These caps were first recognized by Blackburn when she discovered a sequence of DNA, CCCCAA, which was repeated at the end of chromosomes several times during cell division. When she presented her findings in a conference, Jack Szostak was highly interested. He was doing some chromosome research of his own when he discovered a chromosome that was “rapidly degraded” when introduced to yeast. Szostak wondered if the sequence Blackburn discovered during cell creation could help explain the destroying of these chromosomes.
Szostak and Blackburn teamed up to find out the effects of taking the CCCCAA sequence and coupling it with the chromosome that was destroyed by the yeast. They found that the sequence saved the chromosomes from degradation when reintroduced to the yeast. This was the discovery of the telomere and its importance to the protection of chromosomes during cell division. Through this experiment they were able to prove that telomeres are protective caps on chromosomes, and that once they run out, the cell dies.
Blackburn continued her work researching the telomeres and came in contact with Carol Greider at UC Berkeley. Here the two teamed up to find out how telomeres are made. They discovered an enzyme extracted from an organism that contained mRNA holding the sequence for the CCCCAA sequence which makes up telomeres. They called the enzyme telomerase and determined that it helps polymerases copy DNA without loosing any information. This means that with the help of telomerase, cells can continue to divide without loosing their chromosomes.
Blackburn, Szostak and Greider found that on each end of all our chromosomes there is a cap called a telomere, which is made from the enzyme telomerase. Every time the cell divides, this cap gets a little shorter and eventually the cap runs up and the cell can no longer divide. This has lead to the theory that is we can stop these caps from disappearing then we can allow our cells to divide and multiply forever, or at least a lot longer than they do now. Research has also found that telomerase has a habit of overdoing itself in cancer cells, making the telomeres indestructible, allowing for continuous division. Scientists believe if they can stop this they may be able to find a cure for cancer.
On Oct. 22 it was reported that Dorothy Shippen, a biophysics teacher made a new discovery in the telomere world. She, along with a team of other biologists found a set of telomere proteins in humans before only found in plants. Shippen discovered that when this protein was removed from the cell, “rampant end-to-end joining of chromosomes and dramatic defects in plant development” occurred. It was then discovered that when the human version of the protein was removed from cancer cells there was “wide-spread DNA damage and complete loss of some telomeres” and we know through the discoveries of Blackburn and Szostak, when the telomeres are lost, the cells can’t divide. This means a cure for cancer may be very close.
When I first started looking up news about telomeres I came across the two articles about how the Nobel prize was being given to the scientists who discovered telomeres. I was first looking at an article in the Philadelphia Inquirer. Being a major news paper it is a very credible source. However, I didn’t really like the flow of the article. It had no real chronological order with the decade seeming to change every paragraph along with the people it was talking about. This led me to the Nobel Prize website, where I hoped to find more clear information. Because the website is not constrained to news paper format I feel like the writer was able to convey the information a lot better. First off, every section of the article is labeled with a heading, starting with a summary. From then on the information about the three prize winners and their discoveries is laid out chronologically. The article was released by the Nobel Assembly at Karolinska Institutet. Because it was written by the Nobel Assembly I feel the source is more credible and less cluttered, as it is the origin of the information.
After I read about the winners of this years Nobel Prize, I decided to see where their research has gone today. That’s when I found the articles on Dorothy Shippen’s findings. The first article I read was from Eurek Alert. I had never heard of the website but the article looked very credible. The first thing in the article is Shippen’s contact information. The writer must be someone from inside Texas A&M as they give information about ongoing research as well as places to find more news and updates. The other article I read was the actual write up of the experiments done by Shippen and her colleagues. This version was the very technical, scientific version. Its jargon made it almost impossible to read unless you were a scientist or wanted to do a few hours of additional research. The Eurek Alert provided the essential information in a way that the common person could understand, and did it in an interesting way. All the sources I looked at were credible. For the Nobel articles the primary source was more helpful for me while in Shippen’s case, it was the secondary source that did it for me.

Sources used for Nobel Prize information:

http://nobelprize.org/nobel_prizes/medicine/laureates/2009/press.html

http://www.philly.com/inquirer/front_page/20091006_3_Americans_share_Nobel_in_medicine.html

Sources used for Shippen’s findings:

http://www.eurekalert.org/pub_releases/2009-10/tau-cwc102609.php

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WSR-4XHCCH8-9&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=dcb57d5928146b5a1e5ee9b849a53879