Test of correlations between molecular weight and recovery time after photobleaching. (a) The kinetic properties after photobleaching were studied for the following proteins: heterochromatin protein 1α (HP1α), HP1β, B lymphoma Mo-MLV insertion region 1 (BMI1), telomeric-repeat binding factor 1 (TRF1), RNA polymerase I large subunit (RPA194), upstream binding factor (UBF), H2B, H4, ubiquitin (Ub), lamin A (central), JMJD2b, p53, c-MYC, β-catenin, STAT1, α-tubulin, PML, and Oct3/4. α-Tubulin was tagged with mCherry (35 kDa) and other proteins were tagged with GFP (28 kDa). Molecular weights of individual proteins were compared by correlation analysis with the level of relative fluorescence 6 s after photobleaching [R6]. (b) A correlation between molecular weight and fluorescence recovery of proteins was found for proteins that were evenly dispersed throughout the nucleoplasm: HP1α, HP1β, BMI1, TRF1, H2B, H4, Ub, lamin A (central), JMJD2B, p53, c-MYC, β-catenin, STAT1, α-tubulin, Oct3/4. (c) No correlation between molecular weight and fluorescence recovery for proteins that were accumulated into foci: HP1α, HP1β, BMI1, TRF1, and PML. (d) No correlation was detected between molecular weight and fluorescence recovery for proteins accumulated into nucleoli: HP1β, RPA194, UBF. Pearson's correlation coefficient for (n-2) = 17 is 0.456; for (n-2) = 13 is 0.514; for (n-2) = 3 is 0.878 and for (n-2) = 1 is 0.997. These values are for α = 0.05. Regression lines surrounded by 95% confidence intervals (dashed curves) are shown in all panels except panel (d); to unify the axis scale, confidence intervals are not shown.