[Science] We could soon make animals with cells that contain two genetic codes – AI

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[Science] We could soon make animals with cells that contain two genetic codes – AI


Future versions of this cow and these plants could be made with synthetic proteinsE /Getty By Michael Le PageIn the not-too-distant future, there could be fields of crops and herds of animals that produce proteins unlike anything found in nature. A team in Germany has added artificial molecular machinery for making synthetic proteins to human cells growing in a dish. The researchers think it should be possible to create plants and animals that have these designer factories in every cell in their body. “There’s no reason to think this can’t be done in a more complex organism,” says team leader Edward Lemke of Johannes Gutenberg University Mainz in Germany. Proteins are large molecules that carry out key tasks in all living organisms, and are made of just 20 building blocks called amino acids. Making proteins with amino acids not found in nature could have all sorts of advantages, such as creating new materials or treatments for diseases. Lemke and his team want to create fluorescent proteins they can watch in action at a molecular level, for instance, so they can understand exactly what the proteins do. Advertisement The recipes for making proteins are encoded in DNA, in the form of three-letter-long sequences called codons that specify one of the amino acids, or when the recipe should end. The cell makes RNA copies of these DNA recipes when needed and sends them to protein-making factories. Several teams have already tweaked the protein-making factories in cells – and even in fruit flies – to read the most rarely used codon differently and insert an artificial amino acid. The trouble is, any RNA recipe containing that codon is then read differently, so it indiscriminately affects many different proteins. The solution being pursued by most teams is to rewrite genomes to free up codons, which is possible because the genetic code is redundant – there is more than one codon for each amino acid. This has been done in bacteria, but it would require making at least 4000 changes to the human genome to free up just one codon. “This is beyond our reach now,” says Lemke. “Maybe in 10 years.” Read more: Reprogrammed bacterium speaks new language of life So his team engineered human cells to produce two kinds of protein factories instead of one. The artificial one is made of proteins that coalesce together like an oil droplet in water, physically separating them from the rest of the cell. Only RNAs with a special added sequence can get into these designer protein factories, so these cells can use two different genetic codes at the same time without mucking up normal proteins. In other words, the cells can make proteins with several different kinds of artificial amino acids without any need to rewrite the genome to free up codons. “It is really quite ahead of what people believed could be done,” says Lemke. Lemke says he is confident that these designer protein factories could be added to plants or animals. His team plans to try it starting with the Drosophila fruit fly. He thinks a similar approach could be used to add all kinds of other designer “organelles” – the parts with a specialised job – to cells. “We now have the confidence that we could create organelles for other kinds of functionality,” says Lemke. “Our ultimate goal would be complete control over the cell.” Journal reference: Science, DOI: 10.1126/science.aaw2644 More on these topics: life Read More

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