American microbiologists have created a primitive synthetic cell that grows normally and divides with a minimal set of genes. The Cell magazine writes about it.
Scientists from the Venter Institute (JCVI) back in 2010 took the most low-organized and self-reproducing organism – mycoplasma, removed its DNA and instead “stuffed” a genetic code of 473 genes into the cell, which was written on a computer and then synthesized. The “cyber organism” was named JCVI-syn1.0.
Mycoplasma cells are so small (0.15-0.20 microns in diameter) that a hundred or more of them would fit inside one E. coli bacteria. By the way, the latter has about 4,000 genes, and in a human cell – about 30,000.
Since then, the authors have been trying by trial and error (systematically adding and removing genes, and then testing the result in practice) to reduce the genome of a synthetic organism to a vital minimum. If the removal of a gene interferes with the normal process, it is put back in place, and then another is removed.
In 2015, the genome was simplified so much that JCVI-syn3.0, although it divided, was abnormal – with different shapes and sizes of cells, and sometimes it was not completely divided and lined up into a garland.
After that, 19 genes were added to the genome of the organism, including seven of those that, according to the researchers, were needed for normal cell division. The calculations were justified: JCVI-syn3A was neatly divided into homogeneous spheres.
“This result underscores the polygenic nature of cell division and morphology in a genomically minimal cell,” the authors noted.
At the same time, scientists still know the function of only two (ftsZ and sepF) of those seven genes. “We want to understand the fundamental rules of life design, but it still remains a black box,” the authors write.