TABLE 1.

SacY can antiterminate transcription of a chromosomal bgl-lacZ fusion in E. coli^a

Plasmid	Plasmid-encoded protein	Phenotype on MacConkey-lactose mediumb	β-Galatosidase activity (U)c
pMN25	BglG	+	47
pSL85-XΔ1	SacY	+	39
pOACY	SacY	+	51
pBR322		−	3

^aThe experiment was carried out with MA152, an E. coli strain which is Δbgl and carries a bgl-lacZ transcriptional fusion (35). 

^bExpression of the bgl-lacZ fusion was partly determined by colony color on MacConkey-lactose plates: +, red colonies; −, white colonies. 

^cThe values, in Miller units, represent the averages of four independent measurements.