TABLE 1.

Heterokaryon assay cell counts

Transiently expressed proteina	No. of mouse nuclei
	Positiveb	Negativec
Myc-hnRNPA1	63	0
Myc-hnRNPC1	11	46
GFP-13/14	51	2
SV5-13/14	24	2

^aCOS-1 cells were transiently transfected with expression vectors for each of these proteins. 

^bPositive mouse nuclei were counted as those that were present in a fused heterokaryon with monkey nuclei from expressing cells and contained detectable levels of the expressed protein. 

^cNegative mouse nuclei were counted as those that were present in a fused heterokaryon with monkey nuclei from expressing cells but did not contain detectable levels of the expressed protein.