Fig. 1.

macP is essential in cells lacking PBP1a. (A) Transposon insertion profiles for a select region of the chromosome for wild-type and the ∆pbp1a mutant. The height of each line in the profile represents the number of sequencing reads corresponding to a transposon insertion at the indicated genome position. Transposon insertions in the macP gene were significantly (P < 0.0002) underrepresented in the ∆pbp1a mutant relative to wild-type. Virtually no insertions were mapped to the essential gene gluM in either strain. Tn-seq output and statistical data for all libraries used in this study are shown in Fig. S1. (B) Spot dilutions of wild-type D39 ∆cps (wt) and the indicated derivatives. Cells were grown to exponential phase in the presence of 200 µM ZnCl₂. The resulting cultures were normalized to an OD₆₀₀ of 0.2, 10-fold serially diluted, and spotted (5 µL) onto TSA 5%SB plates in the presence or absence of 200 µM ZnCl₂. Plates were incubated at 37 °C in 5% CO₂ and imaged.