Mature mRNAs have been thought to reside predominantly in the cytoplasm, where they serve as templates for protein translation. Bahar Halpern et al. analysed cytoplasmic versus nuclear mRNA pools in pancreas and liver cells and found that, in fact, fully mature mRNAs of a significant fraction of genes (including various metabolic genes) are found in higher amounts in the nucleus than in the cytoplasm. This was attributed to low mRNA export rates in comparison to cytoplasmic degradation rates. Computer modelling based on these data indicated that such a nuclear accumulation of mRNAs might dampen gene expression noise, which originates from the pulsatile nature of transcription. Thus, mRNA nuclear retention could confer robustness to the process of gene expression, without the need to alter the steady-state levels of mRNA.