DNA Methylation

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Introduction: 

            We are all aware that every cell in the body has a different function. The eye cells allow us to see this wonderful planet, the stomach cells help us to digest the delicious meals, and the brain cells allow us to think through hard problems or situations. This list is super long. Have you ever wondered why our eye cells never secret hydrochloric acid just like the stomach cells? Why can’t we see with our nerve cells? Every cell is differentiated, but how? A part of the answer is DNA methylation. Now let us discuss the process of DNA methylation in detail. 

What is DNA methylation?

DNA methylation is an epigenetic1 mechanism to silence the genes from transcribing to RNA. Research on DNA methylation suggests that the cytosine bases are methylated to ensure that the genes are in the “locked” mode. The DNA methyltransferase enzyme converts the cytosine base to 5-Methylcytosine which aids to silence the gene (2). This process is essential to inactivate one X-chromosome2 in the girls. Therefore, this ensures that both the sexes have one active X chromosome. We can also safely conclude that DNA methylation is a crucial process for cell differentiation. To answer the questions mentioned in the introduction, DNA methylation plays a role in why we can’t see through our nerve cells or why our eye cells do not secrete hydrochloric acid. We should express our gratitude as we have avoided a major pathology caused by the acid secretion in the eyes! 

DNA methylation and cancer

Cancer is a genetic disorder that causes uncontrollable cell growth which has the potential to cause numerous problems. The scientists have noticed some abnormal DNA methylation patterns in cancer patients. With that being said, many researchers have concluded that there might be an inverse relationship between gene expression and DNA methylation levels in the cancer cells. Also, the common pattern observed in cancer cells is the extensive hypomethylation of the genes. It means that the traditionally silent protooncogenes3 are activated after these alterations. If these genes are not methylated, it means they have been activated. Moreover, the genes that are traditionally active to suppress any unchecked cell growth, are observed to be methylated in the cancer cells (3). It means that the suppression of the tumor suppressor genes and the activation of the protooncogenes might be a cause for the development of cancer. 

Conclusion:

DNA Methylation is an excellent epigenetic signaling tool that is very crucial for the development of a human being. This technique plays a huge role in cell differentiation and also inactivates the X chromosome in females. However, this technique can be a source for the development of cancer, and hence with research, we can better understand the role of DNA methylation in cancer. 

Notes:

  1. The inherited phenotypic changes which are not involved in the alteration in the DNA sequence 
  2. The inactivated X body is referred to as the Barr body 
  3. When this gene is mutated, then it can be converted to an oncogene, which leads to cancer 

 

Works Cited:

  1. Jin, B., Li, Y., & Robertson, K. D. (2011). DNA Methylation: Superior or Subordinate in the Epigenetic Hierarchy? Genes & Cancer, 2(6), 607–617. https://doi.org/10.1177/1947601910393957
  2. Shiel, W. C. (2017, January 25). Medical Definition of Proto-oncogene. MedicineNet; MedicineNet. https://www.medicinenet.com/script/main/art.asp?articlekey=5088
  3. The Role of Methylation in Gene Expression | Learn Science at Scitable. (2014). Nature.Com. https://www.nature.com/scitable/topicpage/the-role-of-methylation-in-gene-expression-1070/
  4. Wajed, S. A., Laird, P. W., & DeMeester, T. R. (2001). DNA Methylation: An Alternative Pathway to Cancer. Annals of Surgery, 234(1), 10–20. https://doi.org/10.1097/00000658-200107000-00003




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