Gene expression in eukaryotes is regulated at different levels, which need to be coordinated to implement the information in the genome. Now it is clear that post-transcriptional regulation of gene expression such as pre-mRNA splicing, mRNA transport, editing, turnover and translation are as important as the control of transcription. In all aspects of post-transcriptional gene regulation a crucial role for RNA binding proteins (RBPs) has been documented. In fact, RNA polymerase II transcripts are accompanied by the RBPs from the start of the transcription until they are degraded in the cytoplasm