Israeli scientists map genetic-switch involved in controlling human genome

Source: Xinhua| 2019-08-06 01:04:12|Editor: ZD
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JERUSALEM, Aug. 5 (Xinhua) -- Israeli scientists have found a way to reveal the distribution of the chemical tag m6A, which is a genetic switch involved in the control of the human genome, the Weizmann Institute of Science (WIS) in central Israel reported on Monday.

The researchers have also been able to decipher the genetic sequence that encodes the tag's placement.

The findings, published in the journal Cell, can be used to study the role of m6A in various diseases by exploring its distribution throughout different physiological processes and comparing its placement in healthy and disease states of the organism.

Once the role of m6A in the cell is better understood, it may be possible to develop ways of restoring its proper functioning in cases when it is disrupted.

The m6A tag was discovered almost half a century ago, but tools for studying it effectively were until recently limited.

The m6A tag regulates the functioning of RNA, the transient molecules that carry instructions from DNA to the cell's protein-making machinery.

The "m" in m6A stands for a small chemical compound called a methyl group, which attaches itself to the sixth position of an RNA building block called the A nucleotide, ultimately causing the entire RNA molecule to disintegrate.

Less than 1 percent of all the A nucleotides in mammalian RNA are tagged by m6A, but previous studies have shown that errors in this tagging can have far-reaching consequences.

They may, for example, interfere with the growth of an embryo by preventing embryonic stem cells from differentiating into specialized tissue, or they can cause abnormal proliferation of various cell types, leading to leukemia.

Previous methods for detecting m6A, which relied on labeling it with antibodies, could not measure its quantity at specific locations.

In the new study, the scientists developed a quantitative method using an enzyme known to cut RNA molecules at sites containing A and C nucleotides: the ACA sequence.

It has been shown previously that if the m6A tag attaches itself to the first A of the ACA, the enzyme is unable to cut the RNA at that spot.

Thus, the scientists exposed yeast and mammalian RNA to the enzyme, sequenced the resulting RNA fragments and analyzed the sequences - those of the fragments cut by the enzyme and those remained uncut, thus revealing m6A tagging - using advanced algorithms.

The analysis provided a detailed map of m6A distribution and enabled the scientists to learn more about the way m6A chooses where to attach to the RNA molecule.