FIG. 4.

Organization of the S. pneumoniae R6 pur gene cluster and relative transcript amounts from its genes in cells subjected to translation inhibition. (A) Organization of the pur gene cluster that encodes the biosynthetic enzymes that convert PRPP to IMP (see Fig. 5). Each arrow represents an ORF. Flanking ORFs comB and strH are included for reference. (B) The relative fold change in transcript amounts of each gene in the pur cluster determined by independent microarray analyses of RNA from cells treated with sublethal concentrations of translation inhibitors (see Materials and Methods and Results; Table 1). Also shown are the relative fold changes in transcript amounts from the spr0264, xpt, and pbuX genes that mediate purine salvage and uptake but that are not genetically linked to the pur gene cluster (see Results and Discussion). Erm, erythromycin; Cm, chloramphenicol; Pur, puromycin; Tet, tetracycline.