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In a new first for genetic engineering, scientists have developed a single-celled synthetic organism that grows and divides much like a normal cell, mimicking aspects of the cell division cycle that underlies and generates healthy cell life.
The achievement, demonstrated in a single-celled bacteria-like life form called JCVI-syn3A, is the result of decades of sequencing and genomic analysis by scientists, exploring the roles that individual genes play inside living creatures. .
“Our goal is to know the function of each gene so that we can develop a complete model of how a cell works,” says biophysicist James Pelletier of MIT and the National Institute of Standards and Technology (NIST).
While the roots of the work can be traced back to the 1990s, the most recent advancements took place this century, with researchers in 2003 having successfully synthesized a small virus that infects bacteria.
This led to a new breakthrough in 2010, with scientists at the J. Craig Venter Institute (JCVI) in Maryland who designed the first synthetic bacterial cell, called JCVI-syn1.0: the first organism on Earth with a fully genome synthetic, designed by removing the bacteria’s natural DNA Mycoplasma mycoides.
Several years later, the team took another step forward, creating a species of bacteria in the lab with a genetic code smaller than anything found in nature.
This organism, called JCVI-syn3.0, had a total of only 473 genes – shorter than any known living, self-sufficient organism in the natural world.
But while JCVI-syn3.0’s miniaturized genetic toolkit allowed it to perpetuate itself through cell division, it did so in an unusual way, producing “striking morphological variation” in the new cells it did. has created, which have emerged in a variety of different shapes and sizes. .
Now, members of the same research team have found a way to prevent these weird morphologies from occurring, with a newly modified variant of JCVI-syn3.0, known as JCVI-syn3A.
With the addition of 19 genes not present in JCVI-syn3.0, the new JCVI-syn3A is able to undergo cell division in a more normal and consistent manner, with significantly less morphological variation than JCVI-syn3. 0.
Despite the many years of work behind this achievement, there is still a tremendous amount of mystery shrouded in these genes.
For example, while JCVI-syn3A has 19 new genes, only 7 genes would play a role in the conduct of its cell division processes on a more regular basis. And of those seven, only two genes – called ftsZ and sepF – have had their functions identified.
How the other five necessarily contribute to the morphological coherence of JCVI-syn3A remains unknown, but one thing is certain: this tiny genome now represents the new standard of experimentation that could help us characterize exactly what these genes do in the world. inside organisms.
“JCVI-syn3A thus offers a convincing minimal model for bacterial physiology and a platform for the engineering of biology at large”, explain the researchers in their article.
Or, to put it another way, as the leader of the NIST Cellular Engineering Group, Elizabeth Strychalski, puts it: “We want to understand the basic design rules of life. If this cell can help us discover and understand these rules, then we’re off to the races. “
The results are reported in Cell.
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