Figure 8.

Dependence of binding by SRSF1 on oligonucleotide tail sequences. (A) Native gel electrophoresis showing displacement of SRSF1 protein from oligonucleotide 27 by competing bifunctional oligonucleotides. Reactions containing 5′-end-labelled oligonucleotide 27 (six GGA motifs, fully 2′O-methyl modified) were incubated with excess recombinant SRSF1 protein and then mixed with an excess of the oligonucleotide designated above the lanes. The displaced and bound labelled oligonucleotides are marked. (B) Competition between oligonucleotide 27 and untailed oligonucleotide 8 present at an 1800-fold higher concentration. (C) Immunoprecipitation of labelled oligonucleotides with anti-SRSF1 antibody after incubation with recombinant SRSF1. Oligonucleotides are numbered above each lane. The immunoprecipitates and input were analysed by gel electrophoresis and exposed to a phosphor screen simultaneously.