The study, published in the May 21 issue of the journal Molecular Cell, shows that cells sometimes destroy the chemical messages that contain information for making proteins even as the messages are being "read." The work was done by scientists at The Ohio State University Comprehensive Cancer Center Arthur G. James Cancer Hospital and Richard J. Solove Research Institute.
The findings describe a poorly understood biochemical mechanism that cells may use to suddenly stop producing proteins like growth factors that activate genes in response to a hormone or other signaling chemical. The mechanism also plays a key role in Cooley's anemia, which causes the loss of red blood cells in infants and children, and may contribute to changes in gene activation in cancer.
The mechanism involves a recently discovered enzyme that destroys the ribbon-like molecules of messenger RNA (mRNA). Messenger RNA is a copy of gene, and it contains information that describes the structure of a protein. It carries that information from genes in the cell nucleus to the region of the cell where proteins are made.
"Controlling mRNA degradation is one of the key ways that cells regulate how much of a particular protein they produce," says senior author Daniel R. Schoenberg, professor of molecular and cellular biochemistry. "The mechanism we describe is a completely new concept in the field."
Proteins carry out most of the work in cells. Production of a protein begins when the gene carrying the information for a protein opens -- the DNA unwinds -- and the information is copied in the form of another molecule, mRNA.
Next, the mRNA leaves the cell nucleus and enters the cell cytoplasm. There, complexes known as ribosomes attach to one end of the mRNA.