Figure 4

Firre and Dxz4 on the Xi are associated with the nucleolus in female nuclei. (A) Examples of nuclei from Patski cells after DNA-FISH to detect Firre (green signals), immunostaining to detect nucleophosmin (red) on the surface of the nucleolus, and counterstaining with Hoechst 33342 (blue). Firre association with the nucleolus is marked by an arrowhead. One deconvoluted Z section is shown. (B) Frequency of association (in % of nuclei) between the nucleolus and Firre or a control BAC clone (RP23-112D6) in female Patski cells (red) and male ear fibroblasts (blue). P values were determined by one sample t-test. Error bars, s.e.m. (C) Examples of nuclei from Patski cells after DNA-FISH to detect Firre (red), RNA-FISH to detect Xist (green) and mark the Xi, and immunostaining to detect nucleophosmin (blue). One deconvoluted Z section is shown. (D-F) Same analysis as in A-C for Dxz4 (see also Additional file 5: Figure S4D). (G) Firre and Dxz4 on the Xi are separately associated with the nucleolus in female nuclei. Example of nuclei from Patski cells after DNA-FISH to detect Firre (red), Dxz4 (green), and immunostaining to detect nucleophosmin (blue) on the surface of the nucleolus (see also Additional file 5: Figure S4A).