TABLE 2.

Summary of point mutations of helicase A NTD and their ability for nuclear import and export

Mutation	Ability for:
	Nuclear importa	Nuclear exportb
Wild type	+	+
P1160A	+	+
Y1179A	+	+
Y1199A	+	+
R1219G	+	+
G1220A	+	+
F1125L	+	+
ΔR1158	+	+
ΔK1162	−	+
ΔR1165	−	+
ΔY1166	+	+
R1165L	−	NDc

^aThe subcellular localization of all mutants was examined with the mutants as GFP fusion proteins. The wild type, ΔR1158, ΔK1162, and ΔR1165 were also studied as Myc-PK fusions. 

^bFor all the mutants that retained NLS activity, nuclear export was assayed by accumulation of the GFP fusion proteins in the cytoplasm after treatment with 4 μg of actinomycin D per ml. For ΔK1162 and ΔR1165, nuclear export was assayed in interspecies heterokaryons as both NPc-TNLS fusions and GFP-TNLS fusions. 

^cND, not determined.