Purification and Reconstitution of the S. cerevisiae TRAMP and Ski Complexes for Biochemical and Structural Studies.

The RNA exosome is a macromolecular machine that degrades a large variety of RNAs from their 3'-end. It comprises the major 3'-to-5' exonuclease in the cell, completely degrades erroneous and overly abundant RNAs, and is also involved in the precise processing of RNAs. To degrade transcripts both specifically and efficiently the exosome functions together with compartment-specific cofactors. In the yeast S. cerevisiae, the exosome associates with the Ski complex in the cytoplasm and with Mtr4 alone or with Mtr4 as part of the TRAMP complex in the nucleus. Here we describe how to produce, purify, and assemble the Ski and TRAMP complexes from S. cerevisiae.