Fig 1: Disease-causing mutations in FUS or TRIP4 disrupt interactions of ASC-1 complex components with the RNAP II/U1 snRNP machinery. (A) Purified recombinant GST-FUS or GST-DDX39B was added to FUS KO extract, and RNAP II was IP’d followed by Westerns with antibodies to the ASC-1 components. The asterisk indicates degradation products of GST-FUS. Endogenous FUS, GST-FUS, and GST-DDX39B were detected by the FUS antibody, as this antibody recognizes GST-DDX39B due to the GST tag common to both proteins. (B) Three independent replicates of the data shown in (A) were quantitated. The colored bars in the graph show the mean values of fold change for the indicated proteins. Error bars represent standard deviations. *P < 0.05, n.s., not significant (two-tailed Student's t-test). (C and D), same as (A and B), except that GST-FUSG156E or FUSR514G was used for add-backs. (E) HA-DDX39B, HA-TRIP4 or HA-TRIP41-254 was expressed in HeLa cells followed by IP/westerns with the indicated antibodies. (F) Quantitation of three independent replicates of data shown in (E). **P < 0.01 (two-tailed Student's t-test.)