Tip110 association with pre-mRNA and spliced RNA products in the spliceosomes. 32P-labeled human β-hemaglobin minigene pre-mRNA was first incubated with Hela nuclear extract (lane 1). The splicing reaction was then immunoprecipitated with an anti-Tip110 monoclonal antibody (lane 3), or an isotype-mached IgG control (lane 2). The immunprecipitates were subjected to 8% denaturing PAGE. The symbols on the left are pre-mRNA and its splicing products.