TABLE.

 2. Relative changes in transcript amounts of the pdxB-, flk-, and ksgA-specific transcripts and the pdxA-ksgA cotranscript in exponentially growing and amino acid-starved E. coli K-12

Transcripta	Ratio of transcript amounts (unstarved/amino acid starved)b
	relA+ parent strainc	ΔrelA mutantd
pdxB specific	0.8 ± 0.1	0.8 ± 0.2
flk specific	1.7 ± 0.4	1.0 ± 0.5
pdxA-ksgA cotranscript	5.9 ± 0.8	6.6 ± 1.7
ksgA specific	1.6 ± 0.2	0.6 ± 0.1
Total ksgA	2.3 ± 0.3	0.8 ± 0.1

^aSee Fig. 1 and the text for the locations and functions of genes.

^bCells were grown in LB medium supplemented with 0.4% glucose at 37°C to an OD₄₂₀ of 0.65 with shaking. Amino acid starvation was caused by addition of 1 mg of serine hydroxymate per ml (see Materials and Methods) (67). Samples for RNase T₂ protection assays were taken immediately prior to serine hydroxymate addition (unstarved) and 20 min after serine hydroxymate addition (amino acid starved) (see Materials and Methods). Means with standard errors were obtained from several independent experiments

^cThe relA⁺ strain was either NU426 or NU816 (Table 1), which gave similar results.

^dThe ΔrelA strain was NU1892 (NU816 ΔrelA251) (Table 1).