Table I. Summary of protein interactions and FRET efficiencies analyzed by FLIM in nucleoplasm and nuclear speckles in the absence or presence of an inhibitor of transcription.

	Transcription		Transcription inhibition
Interaction partners	Nucleoplasm	Speckles	Nucleoplasm	Speckles
U1 70K–SF2/ASF	++	+++	−	+++
U1 70K–SC35	+++	++	++	+++
U1 70K–U2AF35	−	−	−	−
U2AF 35–SF2/ASF	++	+++	−	+++
U2AF 35–SC35	+++	++	++	+++
HCC1–U2AF35	++	+	++	++
HCC1–U2AF65	++	+	+++	++

The + and − represent the strength of the protein interactions. +++, strong interaction; ++, moderate interaction; +, weak interaction; −, no interaction.