Fig 2.

Screening for HU-sensitive mutants. (A) Distribution of colony density ratio (7.5 mM HU/LB) for all of the Keio Collection mutants. Mutants that were unable to grow on the plate (7.5 mM HU) were selected as the first candidates. (B) After individual spotting tests, 15 HU-sensitive mutants were selected. The mutations were classified into COG-based categories. (C) HU sensitivity of mutants that were classified as being in the translation category (COG category J). Portions (5 μl) of overnight cultures were spotted onto agar plates at the indicated dilution rates. The plates were incubated at 37°C for 24 h. (D) Distribution of nonessential ribosomal protein mutants in the Keio Collection. The vertical axis represents the Z score of each mutant. The numbers represent the colony density ratio (HU/LB).