MRP1/2 are found in the G1 RNP and bind directly to C35. (A) C35-treated and untreated editosome proteins (E) were incubated with 32P-labeled gA6[14] RNA and resolved on 4% (w/v) TBE gel. Protein-bound RNA is indicated as G1–G4 RNP complexes. (B) The RNA-binding proteins identified in the G1 complex by tandem mass spectrometry. The corresponding protein identification numbers in T. brucei and the number of peptide hits are shown. (C) Covalent conjugation of C35 to the NHS-activated beads through its amine group. (D) Western blot analysis with antibodies against MRP2 (top panel) and KREPA1, KREPA2, KREL1, and KREPA3 (lower panel) analyzing mitochondrial lysate (input), unbound (flow-through), and bound proteins with and without RNase A treatment.
