Figure 1.

Identification of truncated forms of U2 snRNA pulled down with Gemin5. (A) Probes #1, #2, #3, and #4, which correspond to the regions shown under the sequence of U2. The secondary structure of mature U2 is shown. (B) Gemin5- hemagglutinin/TEV protease cleavage site/FLAG (HEF)–associated RNA or pull-down input RNA was separated by denaturing urea-PAGE and analyzed by northern blotting with probes #1–4. (C) Reverse-phase LC separation of RNase T1 digest products of U2-tfsL or U2-tfs. The effluent was monitored at m/z 931.10 (m⁷G-capped AUCGp + three methyl residues, MMG-3m; top) or m/z 938.11 (m₃G-capped AUCGp + two methyl residues, TMG-2m; bottom). MMG was present in both digests. (D) The oligonucleotides identified by LC-MS are underlined in the partial sequence of U2 (1–120). The Sm-site is boxed.