This project aims at resolving dynamic distributions of active genes in the 3D context of the nuclear architecture. Briefly, we are studying the migration of a sub population of genes that migrate to the nuclear pore. The end point result of this process, called gene gating, is that derived mRNAs are more rapidly exported from the nucleus to the cytoplasm. Since the turn over of nuclear mRNAs is much more rapid in the nucleus than in the cytoplasm this results in a post-transcriptional increase in gene expression. Our model system includes a colon cancer cell line and the MYC gene. Thus we have been able to show that the mutation of an inidividal transcription factor binding site abrogates this principle leading to a much reduced MYC expression and cell proliferation rates. Our work has been published in Nature genetics and Nature comm. Our approach to explore the gating principle genome wide is based on the Slam-seq technique. Briefly, the cells are pulse labeled with thiol-uridine and then chased for defined periods of time followed by the separation of the cytoplasmic and nuclear fractions of the labeled cells. Following the addition of spike in RNAs (three in total), the purified RNA from these fractions are treated with iodoacetamide (to convert Ts to Cs) followed by the generation of cDNAs and their conversion into libraries. The bioinformatic analyses will include the mapping of unconverted and converted Ts at the 3'-UTR of alla expressed mRNAs. The ratio between the percentage conversion in the cytoplasmic and nuclear fractions will then determine the rate of nuclear export of all expressed mRNAs. The scientific questions to be addressed include: i) How general is the gating phenomenon, ii) are genes encoding specific pathways involved (we already know that a subset of genes encoding the canonical WNT pathway are gated), iii) are earlly induced genes overrepresented among gated genes (to increase responses to environmental cues), and finally iv) do the gated gene organise a network of feed-back and feed-forward networks to amplify the patterns of gated genes once initiated (we know that factors controlling the gating of MYC represent a functional network but we need to know the genome wide perspective of this).