DNA codes for proteins, and, in doing so, is responsible for many processes that take place in our bodies. An important player in the processes that turn a DNA sequence into a functional protein (see figure 1), is messenger RNA, or mRNA. A recent study, published in Nature, has found a way to artificially modify this mRNA. This changes the ‘building instructions’ of the protein and results in a different protein than the one that was originally coded for.
Figure 1: From DNA to protein.(Source: http://www.dna-sequencing-service.com/dna-sequencing/mrna-dna/)
Protein production is not a perfect process. Not even close. Mutations or transcription errors can lead to the formation of a flawed protein. It are these flawed proteins that could potentially be the root of a lot of harm.
In the study, the authors focused on a mutation that leads to a premature ‘stop-signal’, which stops the reading of the genetic instructions before the protein is completed, with bad results. By altering the premature ‘stop-signal’ into a ‘go-signal’ through the use of guide RNA, the researchers were able to restore the regular protein building process. They were able to perform this feat in yeast cells, both in vitro and in vivo.
Since it is estimated that about one-third of known genetic diseases are the result of a flawed protein formation due to premature stop-signals in the mRNA code, this new method might be a significant contribution towards the treatment of cystic fibrosis, muscular dystrophy, and several forms of cancer. This finding might also elucidate how the relatively few genes in humans (we have many genes, but given our complexity, less than might have been expected) could give rise to an incredible array of proteins. While it is known that some genes code for several proteins, this mechanism might explain the great diversity of proteins.
Karijolich, J. and Yu, Y.-T. (2011). Converting nonsense codons into sense codons by targeted pseudouridylation. Nature. 474(7351), pp. 395 – 398. doi:10.1038/nature10165.