(a, b) SAGA was FLAG-HA purified from S2 cells using WDA as bait protein following treatment of the soluble nuclear extract with RNAse A. An ethidium bromide stained agarose gel of the soluble nuclear extract (NE, 10 μL, + and 20 μL, ++) used for immunoprecipitation with and without RNAse treatment (+/− respectively) is shown in panel (a), and a silver stained SDS-PAGE gel of the purified WDA-complexes +/− RNAse treatment is shown in panel (b). (c) Peptides from SF3B3 and SF3B5 are identified at similar levels in SAGA purifications from S2 cells using WDA as bait in the presence and absence of RNAse treatment. Sequence coverage (%) and number of peptides (spectral count) are shown for each polypeptide, relative to the bait protein WDA.