Researchers at Albert Einstein College of Medicine () of Yeshiva University have discovered the first known mechanism by which cells control the survival of messenger RNA (mRNA) arguably biology's most important molecule. The findings pertain to mRNAs that help regulate cell division and could therefore have implications for reversing cancer
's out-of-control cell division. The research is described in today's online edition of the journal Cell.
"The fate of the mRNA molecules we studied resembles a Greek tragedy," said the study's senior author, Robert Singer, Ph.D., co-director of the Gruss Lipper Biophotonics Center and professor and co-chair of anatomy and structural biology at Einstein. "Their lifespans are determined at the moment of their birth." The study was carried out in yeast cells using advanced microscope technology developed previously by Dr. Singer that has allowed scientists, for the first time, to observe single molecules in single cells in real time.
Directions for making proteins are encoded in the DNA sequences of genes, which reside on chromosomes in the nucleus of each cell. But for proteins to be made, a gene's DNA code must be copied, or transcribed, onto mRNA molecules, which migrate from the nucleus and into the cytoplasm where the cell's protein-making machinery is located. For as long as it exists, an mRNA molecule can act as a template for making copies of a protein. So scientists have long suspected that cells must have ways for degrading mRNAs when, for example, a protein starts accumulating to harmful levels. "The cell somehow decides to destroy its mRNA on cue, but nobody knew how this happens," said Dr. Singer.
In their search for such a mechanism, Dr. Singer and his colleagues focused on two genes, SWI5 and CLB2, which code for proteins that regulate the cell cycle, the complex series of steps during which a cell...