For The First Time, A Cell Built From Scratch Grows And Divides
Arthur T Knackerbracket writes:
For the very first time, biologists packed nonliving components into a cell-like membrane, piece by piece, and witnessed the bag of molecules start to behave like life. The lab-made synthetic cell grew, replicated its DNA, and divided, demonstrating the basic functions of a cell cycle.
It's "an impressive step," said Jack Szostak, who studies the origins of life at the University of Chicago and was not involved in the research. "I don't know of any other effort to put together an artificial cell from biological components that has progressed so far."
The cell is not alive by any definition. It can't survive without constant deliveries of food and ribosomes, the machinery needed to make proteins. It has no defenses or a good waste removal system. But it's the strongest demonstration yet that it is possible to generate life from nonlife, a goal that synthetic biologists have been chasing for decades.
"It's a big step forward to this holy grail of making a living thing out of dead components," said Sijbren Otto, a systems chemist at the Stratingh Institute for Chemistry in the Netherlands who was not involved in the work. "It's not completely there yet, but it's definitely getting quite close."
Since these cells were pieced together from scratch, and all the molecular parts were crafted in the lab, scientists can tinker with the system and switch components in and out. "I have a blueprint, I have a full chemical ingredient list of every component," said Kate Adamala, a synthetic biologist at the University of Minnesota who led the new study, which is not yet peer-reviewed. With such flexibility, this kind of synthetic cell could eventually be coaxed to create new materials, such as biofuels and drugs, and help researchers study disease.
It could also give scientists insight into some of their deepest existential questions: What is the minimum needed to sustain life? How could life start? What happens if we alter the biology that composes life on Earth today?
Or, as Adamala put it: "What else can biology do?"
Some 4 billion years ago, a bunch of nonliving molecules got together to form the first protocells. They fed, grew, and divided. Then, over time, evolutionary processes emerged that let these cells change and diversify into many different types, decorating a barren world with all manner of strange beings. A purely chemical world blossomed into a biological one. Scientists cannot agree on how this shift from nonlife to life, or abiogenesis, happened, but some have turned their sights on trying it out for themselves in the lab.
For decades, researchers have taken different approaches to this challenge. Some, like the synthetic biologist John Glass at the J. Craig Venter Institute, are stripping down bacterial cells to their smallest, barest genomes to reveal a cell's minimum requirements to stay alive. Others, like Otto, try to build cells with molecules that differ from those found in Earth biology.
Adamala also works from the ground up, but with biological molecules found in nature today. When she started her lab in 2016, she envisioned assembling a synthetic cell, a proof of concept, that could undergo a complete cycle of cell division using its own genome.
She found an instruction manual in what all known cells have in common: They grow, they duplicate their DNA, they divide, and they evolve. They transcribe their DNA into RNA and then make proteins to carry out these tasks and others that keep a cell running, such as metabolizing molecules for energy. All of this is done inside a lipid membrane, which holds all the necessary materials in one place. Adamala's team needed to build their synthetic cell a genome and supply it with all the materials to carry out those tasks.
They developed and optimized different ingredients, most inspired by other labs, before combining them together inside liposomes - hollow sacs enclosed by a simple lipid membrane. This would serve as the cellular body.
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