A fraction of NOA1 localizes in the nucleolus and interacts with UBF1.

<p>(A) Immunofluorescence staining of endogenous NOA1 in primary mouse myofibers reveals that a fraction of NOA1 is localized in the nucleolus. (B) Quantitative evaluation of confocal images of NIH 3T3 fibroblasts stained with antibodies against NOA1, UBF1 and Fibrillarin. NOA1 and UBF1 or NOA1 and Fibrillarin are co-localized in the nucleolus. Moving average smoothing was applied to fit data points into curves. (C) Pull-down assays demonstrating interaction of NOA1 and UBF1. Recombinant NOA1-His₆ protein was loaded on Ni-NTA beads and mixed with whole cell or nucleoli lysates from C2C12 cells to pull down interacting proteins. (D) Co-immunoprecipitation of NOA1-His₆ with endogenous UBF1 from C2C12 lysates. (E) Addition of RNAse H or RNAse A to pull-down assays increased the efficiency of the interaction between NOA1 and UBF1 while addition of DNAse I had no effect. Scale bars: 10 µm, Zoom scale bars: 1 µM.