Almost everyone with a basic knowledge of biology knows that the four primary DNA nucleotides are guanine (G), cytosine (C), adenine (A), and thymine (T). In the 80's a fifth base, methylcytosine (mC), was found and from this discovery, methylation was shown to play a major role in epigenetic changes. However, over the last few years more bases have been discovered and also synthesized, so it is possible that the current DNA alphabet will expand rapidly in the near future.
Naturally or chemically modified bases:
- mA --> methyladenine (known to be in bacteria, but researchers are still trying to see if this exists in mammals)
- 5hmc --> 5-hydroxymethylcytosine
- 5fc --> 5-formylcytosine
- 5cc --> 5-carboxylcytosine
All of these bases can play a role in stem cell research, such as being able to reprogram adult cells into stem-like cells through demethylation. Also, they can be used to reactivate tumor suppressor genes that may have been silenced through methylation in tumor cells.
Engineered bases:
- "Z" --> 6-amino-5-nitro-2(1H)-pyridone
- "P" --> 2-amino-imidazo[1,2-a]-1,3,5-triazin-4(8H)one
These bases pair together and can form a double helix just like G-C and A-T pairs and provides the potential to build new proteins for medicinal purposes.
References:
New Nucleotides Identified in Human DNA
Sixth DNA base discovered?
Extra DNA Base Discovered
Structural Basis for a Six Nucleotide Genetic Alphabet
Engineered bases:
I had no clue that these existed. This was very interesting. I definitely plan on reading more about these bases.
ReplyDeleteI had just read about this in a news letter I get every month and think its pretty amazing and has so much potential with stem cell research especially tumor suppressor genes. Again, I have a fascination with the p53 gene which is a tumor suppressor gene. Once turned off, it can't be turned back on, as of yet. I wonder if this could contribute to a means of figuring more out about how it functions once turned off or if this could contribute to learning a way to try and turn it back on.
ReplyDeleteWe discussed this in Molecular genetics not that long ago. We can also create new amino acids for proteins in a lab setting. I think it's really cool but also kinda scary. We are learning how to engineer life to what we want it to be. It could be great for curing disease but also horrible in war and fighting. Instead of mustard gas they could release a legion of E.coli carrying these DIfferent amino acids and DNA bases.
ReplyDeleteSuper interesting. I'm wondering how synthetic bases could be used to build new proteins. Proteins with currently unavailable amino acids? I suppose new tRNAs will be required!
ReplyDelete