You probably are familiar with the fact that our DNA contains genes that affect essentially all of our traits. But what you probably don’t know is that our protein-coding genes only consist of less than 1% of our total DNA– scientists are actually unsure as to what the rest of our DNA does. In fact, these noncoding regions are known as “junk DNA” because previously scientists assumed that they were completely nonfunctional. However, researchers now think that these regions may have a role in regulating gene expression. Scientists from Washington State University have recently proposed that one particular region of junk DNA known as VNTR2-1 may affect the expression of telomerase genes.
The telomerase gene codes for an enzyme called telomerase, which produces telomeres. Telomeres are one type of noncoding region found at the end of DNA molecules that stop the DNA from unraveling. However, every time DNA replicates for cell division, the telomeres get shorter, causing them to be less effective. If they become too short, the DNA cannot replicate properly, causing the cell to age and die without reproducing. However, scientists have noticed that some cells such as reproductive or cancer cells tend to have higher telomerase gene activity, which ensures that the telomere length remains the same when the cells divide. This depended on how long a repeating portion of the VNTR2-1 region was.
These results were determined after deleting the VNTR2-1 region in cancer cells—with shortened telomeres, tumors were unable to grow. Additionally, scientists studied the effect of the length of this sequence had by looking at samples provided by people older than 100. Although the number of repeats varied in the group, they were able to establish that there was more telomerase gene activity in those with longer repeats than those with shorter repeats. When further studied, scientists realized that there were fewer people over the age of 100 that had short sequences compared to a control group composed of younger people. However, it should be noted that having longer telomeres does not necessarily ensure a longer life. People with shorter telomere lengths are less at risk of developing cancer than their counterparts. Regardless, it is clear that these results will beneficially impact further aging and cancer research.
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