Toxic chemicals wreak havoc on cells, damaging DNA and other
critical molecules. A new study from researchers at MIT and the
University at Albany reveals how a molecular emergency-response
system shifts the cell into damage-control mode and helps it
survive such attacks by rapidly producing proteins that
counteract the harm. Peter Dedon, a professor of biological
engineering at MIT, and colleagues had previously shown that
cells treated with poisons such as arsenic alter their chemical
modification of molecules known as transfer RNA (tRNA), which
deliver protein building blocks within a cell. In their new
paper, appearing in the July 3 issue of Nature Communications,
the research team delved into how these modifications help cells
survive. The researchers found that toxic stresses reprogram the
tRNA modifications to turn on a system that diverts the cell's
protein-building machinery away from its routine activities to
emergency action. "In the end, a stepwise mechanism leads to
selective expression of protein