Nuclear retention of mRNA in mammalian tissues

Messenger RNA is thought to predominantly reside in the cytoplasm, where it is translated and eventually degraded. Although nuclear retention of mRNA has a regulatory potential it is considered extremely rare in mammals. Here to explore the extent of mRNA retention in metabolic tissues we combine deep sequencing of nuclear and cytoplasmic RNA fractions with single molecule transcript imaging in mouse beta cells, liver and gut. We identify a wide range of protein coding genes for which the levels of spliced polyadenylated mRNA are higher in the nucleus than in the cytoplasm. These include genes such as the transcription factor ChREBP, Nlrp6, Glucokinase and Glucagon receptor. We demonstrate that nuclear retention of mRNA can efficiently buffer cytoplasmic transcript levels from noise that emanates from transcriptional bursts. Our study challenges the view that transcripts predominantly reside in the cytoplasm and reveals a role of the nucleus in dampening gene expression noise. Overall design: we have total of 8 samples all are mice. liver nuclear RNA (2 replicates), liver cytoplasmic RNA (2 replicates), MIN6 (cell line) nuclear RNA (2 replicates), MIN6 (cell line) cytoplasmic RNA (2 replicates)