Figure 2: UNR interacts with MLE.

(a) The interaction of UNR and MLE is direct and stimulated by roX2. Recombinant UNR, MLE and/or trace-labelled roX2 SL678 or a control RNA of similar size corresponding to the 3′-UTR of Toll were mixed in equimolar amounts, UNR was immunoprecipitated and MLE assessed by western blot analysis after optional incubation with RNases A+T1 followed by extensive washing. Nonspecific IgGs were used as negative control. The RNA remaining in the pellet was quantified and normalized to that in the absence of RNase. Quantifications represent the average of two experiments. (b) Interaction of the endogenous proteins. Nuclear extracts were obtained from formaldehyde-crosslinked nuclei and used to immunoprecipitate UNR. Similar reactions with nonspecific IgGs served as controls. The presence of MLE and MSL3 in the pellet was assessed by with western blot analysis. In some reactions the pellet was treated with RNases A+ T1 (lower panel). Full-size blots corresponding to this Figure are shown in Supplementary Fig. 5.