Figure 3.

SC35 reconstitutes pre-mRNA splicing in U2AF-depleted extracts dependent on the presence of functional U1 snRNP. Splicing of PIPβG pre-mRNA in: nuclear extract (lane 1); nuclear extract preblocked with α-U1 oligonucleotide (lane 2); nuclear extract preblocked with α-U1 oligonucleotide and supplemented with SC35 (lane 3); U2AF-depleted extract supplemented with U2AF⁶⁵ (lane 4); U2AF-depleted extract supplemented with U2AF⁶⁵ and preblocked with α-U1 oligonucleotide (lane 5); U2AF-depleted extract supplemented with U2AF⁶⁵, preblocked with α-U1 oligonucleotide, and supplemented with SC35 (lane 6); U2AF-depleted extract supplemented with SC35 (lane 7);and U2AF-depleted extract blocked with α-U1 oligonucleotide and supplemented with SC35 (lane 8).