A synthetic cell with a tiny genome has gone from idea to dividing in the lab, at least for a few generations.
Scientists at the University of Minnesota say they have built a synthetic cell entirely from scratch and watched it complete a full life cycle, including reproduction.
“This is likely the most exciting project I’ve ever worked on,” said synthetic biologist Kate Adamala, a co-lead on the project. “We’ve replicated in chemistry what only used to be possible in biology: the complete set of behaviors of a cell. It proves that the most fundamental functions of life, like growth and replication, do not need a mysterious magical spark.”
The project is called SpudCell. Its genome is 90 kilobase pairs. For comparison, the human genome is about 3 million kilobase pairs, and biologists had previously assumed a living cell would need at least 113 kilobase pairs of genetic data to function properly.
Adamala and her colleagues say SpudCell appears to push that limit. Their research has not been formally published and has not been peer-reviewed, but it has been shared on the website of Biotic, a new nonprofit bioengineering institution Adamala has helped found.
According to Science magazine, SpudCell has hit hurdles in publication. One reviewer at Cell said the project was not real biology.
That may be partly because SpudCell does not fully meet the requirements for real life. It cannot replicate itself over many generations, and it cannot evolve.
Each artificial SpudCell consists of a liposome, a sphere of fats that mimics the outer membrane of a real cell, wrapped around seven plasmids, which are small units of DNA often found in bacteria. Together, those seven plasmids make up the full 90 kilobase pair genome.
The cell also has an in-built protein expression system, which translates the DNA’s genetic instructions into action. The researchers say that lets the cell turn nutrients from the surrounding liquid into useful materials and enables cell division.
According to the researchers, the SpudCell system is capable of “selection, genome replication, growth, resource acquisition via feeding, and genetically encoded division.”
The team says synthetic cell-like systems could one day be designed as mini biological factories to produce organic materials such as drugs, biomaterials, chemicals and other products. Labs already use genetically modified bacteria and other microbes in this way, including in the production of medical-grade insulin.
The researchers say a fully synthetic cell may allow for efficiencies and specificities that surpass existing biotechnologies.
For now, SpudCells last only a few generations. They cannot produce their own protein expression system or regulate their metabolism, so they depend entirely on substances and components in the liquid medium around them.
They also lack a cytoskeleton, the internal scaffolding that supports natural cells. That simplifies the system, but it means they cannot move materials around internally or clear waste.
The research has not yet been peer-reviewed, but a preprint is available on Biotic’s website.
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