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New discoveries show that human cells can write RNA sequences into DNA

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Cells contain a mechanism for replicating DNA into a new set that enters newly formed cells. A machine of that same class, called a polymerase, also produces memo-like RNA messages copied from the central DNA repository of the recipe, allowing it to read proteins more efficiently. However, polymerases were thought to function in only one direction, from DNA to DNA or RNA. This prevents RNA messages from being written back to the genomic DNA master recipe book. Now, researchers at Thomas Jefferson University have provided the first evidence that RNA segments can be written back to DNA. This has the potential to challenge the central dogma of biology and has widespread implications for many areas of biology.


“This study opens the door to many other studies that help us understand the importance of having a mechanism for translating RNA messages into DNA in our own cells,” Thomas Jefferson University. “Human reality Polymerase For example, this finding suggests that RNA messages can be used as templates for repairing or rewriting genomic DNA.

This work was published in the journal on June 11th. Scientific progress.

Dr. Pomeranz’s team began by working with lead author Gulshan Karl Chandra Morley and other collaborators to investigate a very rare polymerase called the polymerase theta. Of the 14 DNA polymerases in Mammalian cellsOnly three do most of the work of replicating the entire genome in preparation for cell division. The remaining 11 are primarily involved in the detection and repair of DNA strand breaks and errors. Polymerase theta repairs DNA, but it is error-prone and causes many errors and mutations. Therefore, researchers have found that some of the “bad” properties of polymerase theta are shared with other cell machines. However, it is another common reverse transcriptase in viruses. Like Pol theta, HIV reverse transcriptase acts as a DNA polymerase, but it can also bind to RNA and read it back into the DNA strand.

In a series of sophisticated experiments, researchers tested polymerase theta against reverse transcriptase from HIV. They show that the polymerase theta can convert RNA messages to DNA, do it like HIV reverse transcriptase, and do better than actually replicating DNA to DNA. I did. The polymerase theta is more efficient and error-free when using RNA templates to create new DNA messages than when replicating DNA into DNA. This suggests that this function may be the main purpose in the cell.

This group, in collaboration with Dr. Xiaojiang S. Chen’s laboratory at USC, can use X-ray crystallography to define the structure and change its shape to accommodate the bulkier RNA molecules. I found that I could do it.

“Our research suggests that the main function of the polymerase theta is to function as reverse transcriptase,” said Dr. Pomeranz. “In healthy cells, the purpose of this molecule may be RNA-mediated DNA repair. In unhealthy cells such as cancer, cell, Polymerase theta is highly expressed and promotes cancer cell growth and drug resistance. It is very interesting to further understand how the activity of the polymerase theta on RNA contributes to DNA repair and cancer cell proliferation. ”


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For more information:
Polθ reverses RNA and promotes RNA template DNA repair. Science Advances (2021). DOI: 10.1126 / sciadv.abf1771

Quote: New findings show that human cells can write RNA sequences into DNA (June 11, 2021) https://phys.org/news/2021-06-discovery-human-cells-rna -Get from sequences.html

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New discoveries show that human cells can write RNA sequences into DNA

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