WASHINGTON – US scientists say they have taken an important step towards making an artificial life form by making a ribosome – the cell’s factory.
The ribosome makes the proteins that carry out key business for all forms of life. Messenger RNA carries DNA’s genetic instructions to a cell’s ribosome, which then cooks up the desired protein.
Every living organism from bacteria to humans uses a ribosome, and they are all strikingly similar.
It is not quite artificial life, but an important step in that direction, said George Church, a professor of genetics at Harvard Medical School, who directed the research with a graduate student.
“If you are going to make synthetic life that is anything like current life . . . you have got to have this . . . biological machine,” said Dr Church. And it can have important industrial uses, especially for manufacturing drugs and proteins not found in nature.
Dr Church stressed that his research had not been published in a scientific journal, the usual route for reporting such work. He presented it over the weekend to a seminar of Harvard alumni.
Dr Church’s group is not seeking to make life in a test tube, but instead to make designer proteins in lab dishes.
“We can . . . go straight into protein synthesis,” he said. He and and postdoctoral fellow Mike Jewett have already synthesised firefly luciferase – the glowing stuff. “We’d also like to make a whole new kind of cell . . . which is a mirror image of a replicating system.”
Most life forms are “right-handed” or “left-handed”, a quality called chirality. Changing chirality is known to change the effects of drugs in the body. For instance, thalidomide, once used to prevent morning sickness, causes severe birth defects. It has left- and right-handed versions and only the “left” version caused the defects – but the marketed drug contained both types.
It may be possible to make other proteins in a lab dish without using living cells, Dr Church said. These may include drugs using a process called rational drug design, when drugs are built molecule by molecule to have a specific mechanism of action.
Viruses do not count as living organisms by most definitions, Dr Church said, and to build the simplest form of artificial, but true life, it would take 151 genes, he and other experts calculate. These 151 genes “would include enough genes to replicate DNA, produce RNA, produce ribosomes and have a very primitive membrane”, said Dr Church. – (Reuters)