Monday, April 23, 2012

T is for Telomeres

Telomeres are the ends of chromosomes. They are particularly important because they keep the ends of chromosomes from deteriorating. During replication a special enzyme, named telomerase, is used to replication the ends of chromosomes. This process is very important on the lagging strand because it works backwards (works 3' to 5' instead of 5' to 3'). To do this, multiple primers must be placed on the DNA (replication can ONLY work 5' to 3', so even though the lagging strand is working 3' to 5', it skips ahead and works backwards). This creates a huge problem when the end of the chromosome is reached because there is no more DNA strand to place a primer on! Instead of just forgetting about those nucleotides and shortening the chromosome each time replication occurs, telomerase comes in to save the day. This is the only example of a reverse transcriptase in our body (viruses use these very often, it's how some are so deadly, like HIV). The telomerase will ad a 3' overhang that is about 12 to 16 nucleotides long. It is made up of several guanine and thymine bases.

Source: http://en.wikibooks.org/wiki/Medical_Physiology/Cellular_Physiology/DNA_and_Reproduction

Without telomeres and telomerase, our chromosomes would be shorter after every round of replication. This would eventually lead to loss of genes, meaning loss of proteins, and eventually our body wouldn't be able to function. Loss of telomeric ends is a theory of why we age and why some people age faster than others. I haven't looked into it personally but that's what I've heard.

Have you heard anything about telomeres and aging? If there is in fact a correlation and we are able to fix degeneration of telomeres, eliminating aging, do you think we should?

1 comment:

Scribbles From Jenn said...

Never heard of telomeres. If we could fix it to cure things like Alzheimer's, then I say YES!

ScribblesFromJenn
Happy A to Z-ing!