. 2019 Dec 10;11(12):1140. doi: 10.3390/v11121140

Table 1.

Effect on the localization of the Env protein, syncytium-forming ability, and Env protein incorporation into virions of the substitution of YXXL sequences in the infectious molecular clones or Env expression vectors.

Plasmid	YXXL Sequence	Mutation	Syncytium-Forming Ability ¹	Localization			Incorporation in Virions ⁵
Plasmid	YXXL Sequence	Mutation	Syncytium-Forming Ability ¹	Whole ²	Early Endosome ³	Trans-Golgi Network ⁴	Incorporation in Virions ⁵
pBLV-IF2	1st YXXL	Y487A	+++	M	−	+	+
	1st YXXL	L490A	+	C	+	+	+
	2nd YXXL	Y498A	++++	M	−	+	−
	2nd YXXL	L501A	+	C	+	+	+
	3rd YXXL	Y508A	+++	M	−	+	+
	3rd YXXL	L511A	+	C	+	+	−
		WT	+	C	+	+	+
pEnv	1st YXXL	Y487A	++	M
	1st YXXL	L490A	+	C
	2nd YXXL	Y498A	++	M
	2nd YXXL	L501A	+	C
	3rd YXXL	Y508A	+	M
	3rd YXXL	L511A	+	C
		WT	+	C

¹ Significance level of altered syncytium-forming ability compared with that of wild-type: +, wild-type level; ++, p < 0.05; +++, p < 0.01; ++++, and p < 0.001. ² M and C indicate that the Env protein mainly localized in the membrane and cytoplasm, respectively. ³ Localization rate of the Env protein in the early endosome: −, below wild-type; +, wild-type level. ⁴ Localization rate of the Env protein in the trans-Golgi network: +, wild-type level. ⁵ Level of incorporation of the Env protein into virions: −, below wild-type; +, wild-type level.