Park, H.Y. et al. Cell Reports 1, 179–184 (2012).

There are many transcripts that are not randomly localized in cells, as has been revealed by imaging of mRNA distribution in both fixed and living samples. Methods for robust, unbiased and quantitative image analysis of mRNA distribution are still needed. Park et al. now describe the use of two measures, the polarization index and the dispersion index to characterize mRNA distribution in cells, while taking cell size and geometry into account. Using these measures, the authors characterize mRNA distribution in fluorescence in situ hybridization images of budding yeast and chicken fibroblasts as well as in live time-lapse images of migrating mouse fibroblasts in which the beta-actin transcript carries GFP-labeled MS2 repeats. This approach should enable the discernment of subtle phenotypes and could possibly be amenable to automation in the future.