'Noise' of Low-Expression Genes May Be Even Lower Than Thought

Some genes are even less "noisy" in their expression than previously anticipated, a new study appearing in Science Advances says. Gene expression relies on stochastic interactions between DNA and proteins, as how often the two interact is shaped by their abundance in cells. Scientists previously found that some genes had higher noise levels than others, like housekeeping genes, whose expression is expected to follow a Poissonian distribution. But in a new study, researchers from Virginia Tech and elsewhere examine cell cycle genes in the fission yeast Schizosaccharomyces pombe that had expression levels fall below that expected minimum. Instead, the distribution of mRNA from those constitutively active genes were narrower than a Poisson distribution and the lower level of mRNA from these genes could be sub-Poissonian. This, they note, suggests that some results cast aside by other investigators for not following a Poissonian pattern may have been valid data. "We saw these minimal fluctuations in one particular organism and cell type, but we really need to check other cells to determine if it is universal," senior author Silke Hauf from Virginia Tech notes in a statement.