For mRNA to be functional it has to be processed by enzymes and packaged with proteins into mRNP particles. These are the entities undergoing nuclear export and cytoplasmic translation. Definition of numerous mRNP features occurs early during mRNA biogenesis in a process coordinated with transcription. Improper mRNP formation leads to nuclear retention and subsequent nuclear degradation of the mRNA in a process involving, among several degradative enzymes, the RNA exosome of 3’ – 5’ exonucleases. We study the “nuclear battle” between productive events of mRNP biogenesis and destruction by nuclear mRNP quality control. Our experimental goals are pursued using yeast genetics, proteomics, biochemistry and cell biology either as independent projects in the lab. or through the collaboration with research labs in the US or Europe. For further information on particular projects contact a lab member. Although our main model organism is the yeast Saccharomyces cerevisiae, we also have on-going projects in higher eukaryotic systems.