The riddle of methylation
Scientists have come closer to creating living "factories"-mutants
Scientists at the Danish Technical University have identified an unexplored mechanism of epigenetic regulation, in which methyl groups are attached to the DNA chain. This will create living "factories" of various chemicals. This is reported in the press release of Scientists discover mystery of DNA methylation.
Article by Jensen et al. Genome-wide systematic identification of methyltransferase recognition and modification patterns is published in the journal Nature Communications – VM.
The researchers found out which specific enzymes, called methyltransferases, are responsible for a certain pattern of methylation in microorganisms. In the future, this will make it possible to create organisms with certain methylomes — collections of methyl groups associated with DNA. Knowing which enzyme leads to the shutdown or activation of a specific gene, it is possible to introduce new genes into a cell in a microorganism and ensure their work.
DNA fragments introduced using genetic engineering methods can be recognized by the body as foreign due to the fact that they are not methylated in the correct way. This is a problem when creating cellular "factories" — organisms that produce medicinal substances, biochemical compounds and food ingredients.
Researchers have constructed various plasmids — circular DNA molecules that store genetic information in bacteria. Plasmids contained methyltransferase genes and certain DNA fragments (motifs) serving as targets for methylating enzymes. After the motifs were methylated, the scientists sequenced (deciphered the nucleotide sequences) of the motifs, finding out which DNA fragments were exposed to the enzymes.
Thus, methylation patterns were determined in two microorganisms: a heat-resistant bacterium Moorella thermoacetica and bacteria Acetobacterium woodii. In total, bacteria have 23 methyltransferase genes and only 12 different DNA motifs. Methylation of 11 motifs was associated with the work of a specific enzyme.
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