Fig. 3.

Photoconversion of Dendra2-tagged SMN confirms mobilization of SMN by FGF-2²³. Live cell photoconversion experiments were performed using HEK293T cells coexpressing pSMN-Dendra2 and pFGF-2²³-ECFP or pFGF-2¹⁸-ECFP or pECFP. SMN-Dendra2 in CBs was photoconverted for 1 s (405 nm). Fluorescence loss was measured 10 s before, 10 s after conversion and then every minute up to 20 min unless the nuclear body left the defined volume. a Example of a SMN-Dendra2 and FGF-2²³-ECFP (not shown) coexpressing cell before and after photoconversion. Scale bar 10 μm. b Averaged photoconversion measurements were fitted to a one-exponential curve and statistically analyzed (n = 10). Coexpression of FGF-2²³-ECFP increased the loss of red fluorescence of SMN-Dendra2 from large nuclear bodies after photoconversion. c The immobile population was significantly decreased after overexpression of FGF-2²³-ECFP; the mobile population of SMN-EGFP was significantly increased compared to the ECFP control. The slow populations were not significantly altered. The recovery halftimes (t _1/2) of the mobile population of SMN-EGFP were non-significantly changed after overexpression of FGF-2²³-ECFP (means ± SEM; *p < 0.05; ***p < 0.001; n.s. non-significant; unpaired two tailed t test)