All of us know that what is Junk food, but have you ever heard about 'Junk DNA'? Every human being is made up of trillions of living cells and each of them contain DNA as their genetic material. This DNA functions for our body by producing different types of proteins. But 98% of our total DNA does not do anything. It only repeats itself. In scientific language, it does not code for any protein so it is called Noncoding DNA. In 1960s the term 'junk DNA' was used firstly for this noncoding DNA. We can say that most of our DNA is junk.
Recently Jiyue Zhu, a professor in the College of Pharmacy and Pharmaceuticals Sciences, published their study in Proceeding of the National Academy of Science (PNAS). In this study they identify a DNA region that significantly influences the aging process in human beings. Surprisingly, this DNA region is located in noncoding DNA or Junk DNA. So according to this research we can say that this junk DNA can play important role in the aging process of human beings.
How this Junk DNA sequence can influence aging?
Actually, We all have an enzyme known as telomerase enzyme. The function of this enzyme is to prevent the degradation of DNA strands. But with every replication, the length of telomerase enzymes decreases and when there is no telomerase sequence left, DNA denaturate or in other words cell dies. We can say that age of cell came to its end and it dies. But in cancer and reproductive cells, this telomerase sequence does not decreases with every replication. Their genes are coded so that the length of telomerase sequence maintained constant. So cancer cell does not dies and replicates at higher rates. Age of their cells increases by telomerase enzyme action. According to this, we can say that telomerase gene action that controls its enzymatic activity can influence age of a cell or a whole organism.
The DNA region founded by Zhu in junk DNA is known as VNTR2-1. It appears to drive the activity of telomerase gene that controls the activity of telomerase enzyme. Firstly it was thought that junk DNA was nonfunctional for us but this study makes a strong comment on that. According to this research, the gene VNTR2-1 present in Junk DNA can affect the telomerase activity and it has been shown to prevent aging in certain types of cells. Knowing how the telomerase gene of this region is regulated and activated and why it is only active in certain type of cells could someday be the key to understanding how humans age, as well as how to stop spreading cancer.
Zhu said that their findings are based on some experiments. A study was conducted that looked at the length of the sequences in DNA samples taken from Caucasian and African American centenarians. An another study followed a group of people aged 100 or above that was conducted between 1988 and 2008. The researchers found that the length of the sequence ranged from as short as 53 repeats or copies of the DNA to as long as 160 repeats. It varies alot and zhu said that the longer sequence length induces the more lenght of telomerase gene. In the first study, they found shorter lengths in African American participants. Researcher said that it does not necessarily mean that if you have shorter gene lenght, your lifespan will be shorter, because it means that the telomerase gene is less active and your telomere length may be shorter, which could make you less likely to develop cancer.So the DNA part that we were thought to be Junk is no more junk now.
Story Source:
Materials provided by Washington State University. Original written by Judith Van Dongen. Note: Content may be edited for style and length.
Journal Reference:
Tao Xu, De Cheng, Yuanjun Zhao, Jinglong Zhang, Xiaolu Zhu, Fan Zhang, Gang Chen, Yang Wang, Xiufeng Yan, Gavin P. Robertson, Shobhan Gaddameedhi, Philip Lazarus, Shuwen Wang, Jiyue Zhu. Polymorphic tandem DNA repeats activate the human telomerase reverse transcriptase gene. Proceedings of the National Academy of Sciences, 2021; 118 (26): e2019043118 DOI: 10.1073/pnas.2019043118
