TABLE 3.

Phenotypic analysis of the mutations altering L856^a

GCN2 allele	Growth on SCb	Growth on 3-ATb	Growth on 5-FTc	Relative eIF2α-P/eIF2α ratio value under nonstarvation conditions
Vector	++++	−	−	None
WT	++++	+++	−	1.0
E803V	++++	+++	+++	4.7
L856A	+	ND	ND	7.0
L856G	++++	+++	+++	5.0
L856R	+	ND	ND	7.0
L856K	+	ND	ND	10
L856H	+	ND	ND	8.5
L856D	+	ND	ND	8.6
L856E	+	ND	ND	6.7
L856Q	+	ND	ND	7.4
L856N	+	ND	ND	6.7
L856T	+	ND	ND	6.5
L856S	+	ND	ND	8.0
L856C	+	ND	ND	6.5
L856P	++++	−	−	None
L856I	++++	++	−	1.0
L856V	++++	+++	−	1.2
L856M	+	ND	ND	6.5
L856F	++++	+++	−	1.3
L856Y	++++	+++	++	4.5
L856W	++++	+++	−	1.3

^aTransformants of gcn2Δ strain H1149 bearing empty vector or the indicated GCN2 alleles were streaked on synthetic complete medium lacking uracil and scored for average colony size after incubating for 3 days at 30°C. Transformants were replica plated to SD plus 30 mM 3-AT (3-AT) or SD plus 0.5 mM 5-FT (5-FT) and scored for growth after 3 to 4 days at 30°C. The relative eIF2α-P/eIF2α ratios were determined by Western blot analysis of whole cell extracts from cells growing in synthetic complete medium lacking uracil and histidine. The Western blot signals were quantified with a scanner and Scion Image software and normalized to the ratio measured for the WT strain. No eIF2α-P was detectable in the vector and L856P transformants. 3-AT^S and 5-FT^S could not be measured meaningfully in those mutants with strong Slg⁻ phenotypes; hence, such results are listed as not determined (ND).

^b++++, colony size or growth of replica-plated patches of cells indistinguishable from that of WT GCN2 cells; −, colony size or patch growth identical to that of gcn2Δ cells; +, ++, and +++, three classes of colony size or patch growth intermediate between that given by gcn2Δ and GCN2 cells.

^c+++, growth of replica-plated patches indistinguishable from that of GCN2-E803V cells; −, patch growth identical to that of GCN2 cells; + and ++, two classes of patch growth intermediate between that given by GCN2-E803V and GCN2 cells.