Fig. 4. Association of injected Xlsirts and VegT RNAs with the cytokeratin filaments in stage VI oocytes. (A) Texas Red-labeled synthetic RNA (red) was injected into stage VI oocytes, cytokeratin was labeled with FITC-conjugated antibody (green), and vegetal cortices were observed under a fluorescence microscope. In Xpat RNA-injected oocytes, particles of Xpat RNA were visible outside of cytokeratin filaments (1, arrows). In VegT RNA-injected (2,3) and Xlsirts RNA-injected (4) oocytes, RNA particles were concentrated around and on the cytokeratin filaments (arrows). Scale bar: 500 nm. (B) Student's t-test statistical analysis of the number of RNA aggregates associated with cytokeratin filaments showing the statistically significant difference (P=0.03) between the number of aggregates in VegT and Xlsirts versus Xpat RNA-injected samples. Each bar represents the average (with the standard deviation) number of RNA aggregates counted in eight independent samples along the 2 µm length of cytokeratin filament in each experimental group.