Figure 5.

PTBP2 binds switch transcripts in vitro. His-tagged PTBP2 was immobilized on Ni²⁺-agarose beads and incubated with in vitro transcribed radiolabeled RNA. Beads were washed and the amount of radioactivity retained on the beads determined in a scintillation counter, subtracted from the count retained by a control protein (Gen1) and plotted as percentage of total input counts. Controls 1-4 represent transcripts derived from 4 protein-coding genes (#1, Protein kinase A Cα subunit, #2, Protein kinase A RIα subunit, #3, Ku70, and #4, AID). Smu1 and Smu2 contain, respectively, 1 kb and 3 kb S_μ RNA sequence in the sense orientation and SmuR represents a 1 kb anti-sense S_μ transcript. Values in the histogram represent the mean of three independent binding experiments and error bars represent standard deviation from mean. P-values were determined by using the Student's t-test, using RNA#1 as the non-S region control.