Friday, April 30, 2021

Outside the Nucleus: Cytoplasmic DNA Synthesis linked to Degeneration.



        In the article Human Cells Can Synthesize DNA in Their Cytoplasm” scientists have reports which have identified mammalian DNA to be found in the cytoplasm when they would usually find foreign DNA there. However when complementary DNA (cDNA) was discovered to have been synthesized from RNA scientists were baffled. This is due to the fact that because of the mechanism in which they insert copies of themselves into the genome occurs in a copy and paste pattern where such an event usually occurs in the nucleus. Studying cDNA found in the most abundant retrotransposon Alu, when concerning degenerative eye diseases the cDNA of Alu in humans is found to be synthesized in the cytoplasm. 

        Based on previous studies with Alu and other retrotransposons, the way in which reverse transcription occurs in the nucleus considers that it needs a short nucleic sequence, and primer bound to the RNA template to start. However for Alu to undergo reverse transcription in the cytoplasm the nucleic sequence is not present. Which led to the hypothesis that the RNA folds on itself which is also known as self-priming. The cytoplasmic discovery also correlated that age-related macular degeneration (AMD) is due to the cell death of the retinal pigment epithelium because of the abundance of Alu. Since learning of cDNA synthesized Alu connection to the eye degenerative disease it has also been linked to causing inflammation. To manage AMD scientists developed Alu inhibitors which would control Alu accumulation and even treat other infections. The drug which was developed NRTI is said to prevent inflammation and intercept transcription. Since the current drug is in clinical trial it could help cure a degenerative disease which ultimately leads to permanent blindness. With the development that DNA synthesis can  occur without a nucleic sequence to start transcription it is possible to learn that this mechanism could be responsible for other diseases that currently do not have treatments or most effective treatments. 



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