TABLE 1.

Properties of truncation mutants of selected Env proteins

Property	Result for indicated varianta
	ΔR	2-622*	2-623*	2-625*	2-627*	4-622*	4-623*	4-625*	4-627*
Gel migrationb		Unchanged	Unchanged	Unchanged	Retarded	Unchanged	Unchanged	Unchanged	Retarded
Syncytium formationc	++	++	++	+	+	++	++	+	+

^aVariants were named according to the position of the inserted stop codon.

^bGel migration was compared to that of the ΔR variant.

^cSyncyitia included, on average, 5 to 10 (+) or >20 (++) nuclei.