Editing DNA to rewrite a cell's genome

Rewriting DNA can one day help to make artificial proteins or make bacteria that is resistant to viral infection.
Written by Boonsri Dickinson, Contributing Editor

The old saying if it ain't broke, don't fix it doesn't exactly apply to DNA. MIT and Harvard researchers developed tools for rewriting the genetic code of a living cell. Though, it's not the code of life of humans that scientists are tinkering with: It's bacteria.

DNA has a string of letters that code for amino acids, but it turns out the genetic sequence can be rewritten in the same way words can be replaced in a word document, according to an MIT news release.

Think about how the find and replace function works in Word. In DNA speak, this means researchers looked for specific codons and replaced it with new letters: The TAG codon was replaced with TAA 10 times, in 32 E. coli strains. The researchers claim they did this without harming the cells, Popular Science reports.

“When you’re making so many intentional changes to the genome, you might think something’s got to go wrong with that," Peter Carr, senior research staff at MIT’s Lincoln Laboratory, said in a statement.

The researchers used multiplex automated genome engineering (MAGE) and conjugative assembly genome engineering (CAGE) to mix up the genetic code. MAGE is sort of this evolution machine that can selectively change parts of the genetic code. CAGE on the other hand, lets the bacteria swap genetic information. The researchers have control over which parts of the genome they want to change.

The researchers edited parts of the genome of E. coli, without messing with how the cell was functioning. The fact that scientists can do this is critical, because the technique of editing the genome this way is much faster and more reliable than conventional methods. The stakes are high - one mistake in the editing process can be lethal. The work took seven years, with the help of Harvard's geneticist George Church.

In the future, the ability to rewrite the code of life, could be used to help scientists build artificial proteins or engineer bacteria more fit to be resistant to infection, the scientists say. For instance, in industry when viruses can muck up 20 percent of cultures, so editing the DNA structure of the cell could fix this problem.

Indeed, editing the genome of a living cell has future implications. Scientists could take control of the cell, and encode a new protein or tweak the cell so it performs an entirely new function. With every replacement, you run the risk that the cell loses its function.

So far, in this lab at least, the editing looks clean and accurate. And the cells have managed to maintain their function.

Scientists unveil tools for rewiring the code of life [MIT News Office] via Popular Science

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