Dithiothreitol (DTT) acts as a specific, UV-inducible cross-linker in elucidation of protein-RNA interactions

In the present paper, we introduce dithiothreitol (DTT) as a potent protein-RNA cross-linker. To prove this three model systems, a) a small synthetic peptide from smB'/B protein incubated with U1snRNA oligonucleotide, b) in vitro reconstituted 15.5K protein with U4 snRNA oligonucleotide and c) native ribonucleoprotein-complexes (RNPs) from S. cerevisiae were used . All protein-RNA complexes were UV irradiated and heteroconjugates cross-linked enriched prior to LC-MS analysis. Our results unambiguously show that DTT covalently participates in cysteine-uracil crosslinks which is observable as a mass increments of 152 Da upon mass spectrometric analysis.