DNA Structure and Function

Question: Discuss the role of DNA supercoiling in genome structure and regulation? Answer: DNA (Deoxyribonucleic acid) is the molecule carrying the genetic instructions that are needed for the functioning, development and reproduction of al living organisms and many viruses. DNA supercoiling is the under- or over-winding of the DNA strand and is the expression of the strain on the strand (Corless, 2014). The present paper discusses the significance of supercoiled DNA. According to Sinden (2012) supercoiling of DNA is significant for some biological processes, like compacting DNA. DNA supercoiling has a strong impact on the DNA metabolism and therefore gene expression by modifying access to the genetic code. Moreover, particular enzymes like topoisomerases can change DNA topology for facilitating necessary functions like transcription and DNA replication. As pointed out by Forties Wang (2014), DNA supercoiling is necessary for DNA packaging in all cells and this lies the biggest significance of the supercoiling structure. Since the length of DNA is thousand times that of the cells, packaging of the genetic material into the nucleus or the cell is a difficult process. Supercoiling of DNA decreases the space and allows the DNA to be packaged in an effective manner. Supercoiling is also needed for RNA and DNA synthesis. For such synthesis process, there is a requirement for supercoils. Baranello et al., (2012) highlights the role of DNA super coiling in gene expression. Twists in the structure of the DNA exposes internal bases to the outside. Moreover, super coiling leads to tightening of some parts of the DNA and loosening of some other parts of it. This enhances the gene expression as all bases are expressed. The supercoiling trigger stresses along the length and trigger points at allows for gene expression and replication. Referecnes Baranello, L., Levens, D., Gupta, A., Kouzine, F. (2012). The importance of being supercoiled: How DNA mechanics regulate dynamic processes.Biochimica et Biophysica Acta (BBA)-Gene Regulatory Mechanisms,1819(7), 632-638. Corless, S. (2014). Role of DNA supercoiling in genome structure and regulation. Forties, R. A., Wang, M. D. (2014). Discovering the power of single molecules.Cell,157(1), 4-7. Sinden, R. R. (2012).DNA structure and function. Elsevier.