Table 1. Splicing factors bound to IE3 and its mutant by Mudpit analysis.

Splicing Factors	Calculated mass (Da)	Spectrum count
		IE3	IE3mut
Specific Binding
hnRNP H1	49229	355	140
hnRNP F	45672	162	93
hnRNP H2	49264	80	31
hnRNP U	90480	69	18
hnRNP H3	36926	22	0
Non-Specific Binding
NONO	54232	663	621
SFPQ	76150	424	526
SRSF1	27745	109	89
hnRNP A2/B1	37430	53	66
PTBP1	57221	42	60
hnRNP A1	38846	25	25
hnRNP L	60187	17	23