The cellular mechanism that turns DNA into all of the thousands of proteins that make up a human body is itself both intricate and interesting.
A key player in the process—called transcription—is the enzyme RNA polymerase III. Work published online this week in the open-access journal PLoS Biology reports that a mutation of this enzyme prevents cell division, but surprisingly, only affects the development of specific organs. It may also have a therapeutic application against cancer.
A team of researchers led by Dr. Michael Pack, at the University of Pennsylvania, investigated the mutation in RNA polymerase III of the zebrafish, an animal model system that is increasingly being used to study human development and disease. Seventeen different subunits combine to form the RNA polymerase III enzyme in organisms as diverse as yeast, zebrafish, and humans. The mutation they studied, which is called slim jim (because mutant fish are comparatively thin due to developmental differences), affects only one of these subunits. This subtle change is enough to prevent cells from dividing, because with disrupted transcription machinery, a cell is unable to make enough protein to give rise to two daughter cells.