Origin and functional role of antisense transcription in endogenous and exogenous retroviruses

Retrovirology

Table 1 Antisense transcription activity in endogenous and exogenous retroviruses

Retrovirus	Genus	Species	Bidirectional LTR	Antisense transcript	Distribution and function of transcript	Antisense protein	Distribution and function of protein
Exogenous	Gamma-	MLV	P	?	?	?	?
	Delta-	HTLV-1	P	Hbz	Primarily nucleus Promotes cell survival and proliferation Encodes HBZ	HBZ	Nucleus Promotes viral latency and persistence
		HTLV-2	P	Aph-2	Unknown distribution Encodes APH-2	APH-2	Nucleus Inhibits viral replication
		HTLV-3	P	Aph-3	?	APH-3	Nucleus, cytoplasm Inhibits LTR activity
		HTLV-4	P	Aph-4	?	APH-4	Nucleus Inhibits LTR activity
		STLV	P	Sbz	?	SBZ	Nucleus Promotes viral latency and persistence
		BLV	P	AS1, AS2	Nucleus Promote cell proliferation	O	O
	Lentiviruses	HIV-1 (M)	P	Ast, ASP RNA	Primarily nucleus Promotes latency Encodes ASP	ASP	Nucleus, cytoplasm, cell surface, viral envelope Unknown role
		FIV	P	P	?	O	O
		BIV	P	P	?	O	O
Endogenous	Class I	HERV1	P	?	?	O	O
	Class I	HERV9	P	?	?	O	O
	Class II	HERV-K	P	P	?	O	O
	Class II	muIAP	P	P	?	O	O
	Class III	muERV-L	P	P	?	O	O

Gamma- = Gammaretroviruses; Delta- = Deltraretroviruses; ? = unknown, not reported; P = reported, confirmed; O = absent, not found

ISSN: 1742-4690