Skip to main content
. Author manuscript; available in PMC: 2013 Jan 1.
Published in final edited form as: J Struct Biol. 2011 Nov 12;177(1):152–159. doi: 10.1016/j.jsb.2011.11.005

Fig. 2.

Fig. 2

Constitutively and alternatively spliced mRNAs of endogenous human SMN transcripts are associated with supraspliceosomes. (A) Immunoprecipitation (IP) of SMN splice isoforms. A nuclear supernatant enriched for splicing-active complexes was fractionated in a glycerol gradient as described (Azubel et al., 2006). Gradient fractions were pooled together: fractions 1-4 (bottom); 8-11 (200S); and 17-20 (top), and were each treated with immobilized anti-Sm monoclonal antibodies (Y12 MAb). The unbound and bound material (PPT, precipitate) was analyzed by RT-PCR, using SMN primer pairs. Immobilized normal rabbit serum (NRS) was used as a non-relevant control. The two isoforms of the alternatively spliced SMN transcripts are schematically drawn on the left (the alternative exon is marked). (B) Western blot (WB) analysis of precipitated supraspliceosomes, using anti-Sm MAbs (lanes 1-3) and reprobing of the same membrane with antibodies against the ribosomal protein S14 (lanes 4-6). Lane 1, Nuclear supernatant; lane 2, IP from the supraspliceosome fractions; lane 3, unbound material from the supraspliceosome fractions.