Table I. The stimulatory sequence is not the –2 codon.

Sequencea							Readthrough efficiency (%)b	Vector name
GGA	ACA	CAA	TAG	CAA	TTA	CAG	23	(pAC-TMV)
G	T	Q	*	Q	L	Q
AAA	CCA	CAA	TAG	CAA	GAA	TAT	2.2	(pAC-CAAp)c
K	P	Q	*	Q	E	Y
---	TCA	---	---	---	---	---	2.4	(pAC-CAAs)
---	S	---	---	---	---	---
---	GCA	---	---	---	---	---	2.1	(pAC-CAAa)
---	A	---	---	---	---	---
---	ACA	---	---	---	---	---	2.2	(pAC-CAAt)
---	T	---	---	---	---	---

^aSequences derived from the CAAp motif. The amino acids are presented below the nucleotide sequence. The modified nucleotide is indicated in bold, while – indicates unchanged nucleotides.

^bThe assays were carried out using at least three independent transformants. The standard error of the mean of all data presented in this article is <10%.

^cThis sequence has been identified in the PDE2 gene of S. cerevisiae (O. Namy, unpublished).