According to this rule, information flows from nucleic acids, through RNA and to proteins, but never from proteins to nucleic acids.
This has been the fundamental rule in molecular biology, until recently a group of scientists discovered a bacterial defence system, a reverse transcriptase called DRT (Defence associated reverse transcriptase); that uses its own protein structure as a template to synthesize DNA.
When a virus infects a bacterium, the enzyme DRT gets activated and uses its own protein structure as a blueprint, to synthesize dinucleotide repeat DNA sequences (such as -GTGTGT…) which triggers an antiviral immune response.
This research is really significant as it is the first documented exception to the “Central Dogma”. The discovery opens the door to new advances in recombinant DNA technology. However, this does not mean that proteins are also routinely synthesizing DNA in human cells.
How exactly does a protein’s three-dimensional structure guide nucleotide incorporation?
As a bioinformatician, I find this discovery an outstanding breakthrough, as in this case, the protein’s 3D structure creates a molecular template that spatially positions catalytic residues, directing nucleotide selection and repeat synthesis—the structure itself becomes information. Further research on this is going to change our understanding of how biological information is transferred!
What fascinated me most is that this discovery doesn’t replace the central dogma even it expands our understanding of what’s biologically possible. It shows that biology still has exceptions waiting to be discovered.
I’m especially curious whether studying DRT’s 3D structure could inspire new tools for synthetic biology or programmable DNA engineering in the future.
Important paper as far as advancements in molecular biology is considered. Since the inception of central dogma by Crick; scientists working around world have already found many exceptions in central dogma. The most common ones are retroviruses like HIV, which can do reverse transcription i.e. RNA to DNA; RNA viruses like influenza and SARS-COV-2, which uses RNA as template to make RNA; and Prions, the infectious proteins, which makes another infectious proteins by using protein template.
Proteins that play an important role in DNA formation are DNA polymerase, helicase, primase, ligase, and topoisomerase. These proteins cooperate in DNA unwinding, the initiation and formation of the DNA strand, and linking of the fragments, which makes possible DNA formation and the transmission of genetic information.
I recently started learning molecular biology, so reading this was both surprising and exciting. I always thought the Central Dogma was a fixed concept, but it’s fascinating to see how new discoveries can challenge what we learn in textbooks. It makes me curious about how many more exceptions science is yet to uncover.
