Table 1.

Concentrations and properties of expressed fluorescent proteins.

	NE1	NE2	NE3
	mEGFP‐SRSF1	mEGFP‐SRSF1	mEGFP‐SRSF1	mCherry‐U1A
Concentration in extract (µM)	1.5	0.72	n.d.	n.d.
% tagged:endogenous	90:10	59:41	58:42	57:43
Molecules bleaching in 2 vs 1 steps, +ATP	32:129	9:118	18:138	15:124

Concentrations were calculated from Western blotting of nuclear extract alongside recombinant protein; the percentages labelled or unlabelled (endogenous) were also calculated by Western blotting; the numbers of molecules recorded as bleaching in one or two steps when not associated with exogenous RNA are shown. n.d., not determined.