This initiative aims to bring together researchers from disciplines as diverse as systems biology, biochemistry, structural biology and bioinformatics to develop and apply methods allowing insight into the composition of mRNPs, how they are assembled and remodeled and how they function in specific cellular settings. To “decipher the mRNP code”, our overarching goal, we propose to combine data of individual disciplines and projects and subject them to a systematic computational analysis. This will enable the recognition of general principles and patterns of gene regulation by components of the mRNP. We believe that understanding the mRNP code will change our view of how the regulation of gene expression at the post-transcriptional level is accomplished. In addition, as many known diseases have their cause in defects in mRNP metabolism, the proposed topic is expected to have also major impact for biomedical research.