The mystery of lncRNA has been solved
Biologists have found out the purpose of mysterious genes
Biologists from the University of Pennsylvania have found out what long non-coding RNAs (lncRNAs) are needed for, whose role in the genome has long remained unknown. It turned out that even if the RNA itself does not perform any function, the gene encoding it can be a regulator of the activity of another gene. The study was published in the journal Molecular Cell (Paralkar et al., Unlinking an lncRNA from Its Associated cis Element – VM). The press release Function of Mysterious RNAs May Often Lie in Their Genes is available on the website of the University of Pennsylvania.
Picture: Joshua Stokes, St. Jude's Children Research Hospital – VM
lncRNAs, whose length reaches at least 200 nucleotides, are abundant in cells, but these molecules do not contain information about the protein sequence and do not participate in the regulation of genes. They differ in the latter from small non-coding RNAs.
In previous work, scientists were able to identify more than a thousand different lncRNAs in mouse and human cells. Biologists have discovered that the genes encoding them are located in the area of DNA where enhancers are contained – short sections that bind to molecules called transcription factor, and thus enhance the activity of neighboring genes.
In a new study, scientists have studied the function of the enhancer, which is located at the very beginning of the Lockd gene encoding one of the many non-coding RNAs. lncRNAs of this gene are found in the red blood cells of mice and in some other cell types. One possibility was that they perform an unknown function in cells, the other was that the Lockd gene itself plays a role, and its RNA is just a by–product.
The promoter of the Lockd gene – the launching pad for the process of lncRNA synthesis – contains sites with which transcription factors bind. They lie close to the neighboring cdkn1b gene, which encodes a protein important for the regulation of cell division. It turned out that when Lockd is removed, cdkn1b activity is reduced by 70 percent. At the same time, suppression of lncRNA synthesis with intact Lockd does not affect cdkn1b in any way.
Scientists have found out that the promoter of the Lockd gene, due to the twisting of the DNA molecule, comes into contact with the promoter of the cdkn1b gene and, thus, acts as an enhancer that enhances the activity of the latter.
The researchers emphasize that their discovery does not mean that lncRNA itself does not play any role, but for the first time it has been shown that genes and their corresponding RNAs can perform various functions.
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08.04.2016