Eukaryotic gene expression is a multistep process of high complexity. Transcription is one of the cardinal and tightly regulated phases of gene expression. To provide accurate and precise work of the gene regulation apparatus, including a plethora of modifications of the chromatin structure and nucleosome, dynamic turnover must take place. All transcription steps are under the control of large multiprotein coactivator complexes. In this review, we discuss the evolutionary conservative SAGA complex, which acetylates and deubiquitinates histones during transcription activation and, furthermore, is involved in subsequent stages of mRNP biogenesis and export.