TABLE 1.

Recovery of rHPIV1 bearing codon substitution mutations at amino acid position 942 in the L protein

Virus	Codona	No. of nucleotide changes needed to restore wild-type amino acid	rHPIV1 mutant recovered	Adventitious coding mutations in L ORF
rHPIV1 wild type	TAT, TAC	0	+	NDb
rHPIV1-Y942H	CAC	1	+	None
rHPIV1-Y942Cc	TGC	1	+	None
rHPIV1-Y942F	TTT	1	+	None
rHPIV1-Y942Nc	AAC	1	+	None
rHPIV1-Y942Dc	GAC	1	+	None
rHPIV1-Y942S	AGC	2	+	None
rHPIV1-Y942W	TGG	2	+	None
rHPIV1-Y942Q	CAG	2	+	S1302N
rHPIV1-Y942K	AAA	2	−d	ND
rHPIV1-Y942I	ATC	2	−	ND
rHPIV1-Y942E	GAG	2	−	ND
rHPIV1-Y942Mc	ATG	3	+	L1367S
rHPIV1-Y942A	GCG	3	+	None
rHPIV1-Y942Tc	ACA	3	+	None
rHPIV1-Y942G	GGG	3	+	None
rHPIV1-Y942Vc	GTG	3	+	G1755Q
rHPIV1-Y942Lc	CTG	3	+	None
rHPIV1-Y942R	CGG	3	−	ND
rHPIV1-Y942P	CCG	3	−	ND

^aIn the case of wild type, the two possible codons yielding the wild-type amino acid for tyrosine (Y) are shown; for each mutant, the codon chosen for introduction into rHPIV1 is shown.

^bND, not done. The L gene sequence was not confirmed either because the virus is the previously sequenced wild type or because the virus was not recovered.

^cVirus was recovered with pTML containing the indicated codon substitution. The other viruses were recovered using wild-type pTML.

^d−, not recovered.