Genome complexity: organizing the DNA library (Introduction)

by David Turell @, Saturday, November 06, 2021, 21:05 (873 days ago) @ David Turell

Non-coding RNA makes compartments of info:

https://phys.org/news/2021-11-vast-library-cells.html

"The human genome can be thought of as a massive library, containing over 20,000 different "instruction manuals": your genes. For example, there are genes which contain information to build a brain cell, a skin cell, a white blood cell, and so on. There are even genes that contain information about regulating the genome itself—like books that explain how to organize a library. The ability to regulate gene expression—in other words, the cell's ability to turn various constellations of genes on or off—is the basis of why different cells (such as a muscle cell or a brain cell) have different forms and functions.


"For any library to be useful to a reader, it needs to be organized in an easily searchable way. For example, all the books pertaining to world history may be on one shelf, whereas the cookbooks may be in an entirely different section of the library. In a cellular nucleus, there is over six feet of genetic material packed into a space 50 times smaller than the width of a human hair. How is the "library" in the nucleus organized? When a cell needs to regulate certain genes, how does the cellular machinery find the right ones amongst 20,000 others?

***

"Led by former Guttman lab graduate student Sofia Quinodoz (Ph.D. '20)—now a Hanna Gray postdoctoral fellow at Princeton University—the team found that molecules of non-coding RNA are responsible for establishing "compartments" within the nucleus and shepherding in key molecules to precise regions in the genome. Noncoding RNA are molecules that do not encode for proteins, and instead have an array of functions that are often still mysterious to biologists. In the library analogy, non-coding RNA molecules act as the "shelves" that organize different groups of genes and the machinery that interacts with them.

"Understanding how genetic material is organized spatially is a crucial part of understanding the basic workings of life. Dysfunction within the nucleus is a hallmark of many diseases, including cancer, neurodegenerative disorders, and others."

Comment: "Instruction manuals" means information. This is another example of the 3-D understanding of how DNA works to offer coded information. Not by chance


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