TABLE 3.

Suppression of cosB or cosN mutations: crosses between λ cosB or λ cosN and plasmids bearing various Nu1 or A alleles^a

Phage	Plasmid	Allele	PFU/ml
λ-P1 cosB R3− R2− R1−
	pTSNA A-E515G	A-E515G	10
	pTSNA A-N509K	A-N509K	15
	pTSNA A-R504C	A-R504C	25
	pTSNA	A+	10
	pRV5	Nu1ms1	7.6 × 105
	pRV39	Nu1ms2	2.0 × 104
	pRV7	Nu1ms3	1.5 × 105
	pRV12	Nu1+	15
λ-P1 cosN G2C C11G
	pRV5	Nu1ms1	3.9 × 102
	pRV39	Nu1ms2	5.5 × 102
	pRV7	Nu1ms3	7.7 × 102
	pRV12	Nu1+	4.5 × 102
	pTSNA A-E515G	A-E515G	9.1 × 105
	pTSNA A-N509K	A-N509K	4.7 × 105
	pTSNA A-R504C	A-R504C	1.6 × 105
	pTSNA	A+	1.5 × 103

^aPhages are in a λ-P1:5R cI857 Kn^r background. Crosses were performed by inducing plasmid-bearing MF1427 cells lysogenized with cosB R3⁻R2⁻R1⁻ or cosN G₂C C₁₁G phages. The cross lysates were plated on MF1427. The pRV5, pRV39, and pRV7 plasmids are called rev1, rev9, and rev6, respectively, in reference 11.