Table 1.

Variation in viral orf-I proteins

	Protein	mRNA	Size (aa)	References
HTLV-1A	p12/p8 ?	orf-Ia rex-orf-Ib	99 152	[44, 124]
HTLV-1B	?	?	?
HTLV-1C	p16	rex-orf-Ib	153	Our unpublished data
HTLV-2	p10 p11	rex-orf-Ib tax-orf-Vb	83 83	[91]
STLV-1	p12/p8	orf-Ia	86/91	[129]
STLV-3	p9	orf-Ia	79	[92]

? indicates that the data remain unknown

^aSingly spliced

^bDoubly spliced