FIG 4.

EUO target genes are transcribed at higher levels in Pgp4-deficient strains. Shown is qRT-PCR analysis of selected chlamydial genes in L929 cells infected with parental or Pgp4-deficient strains of C. trachomatis serovar L2 (A) or C. muridarum (B). omcB, copB, ctl338, and hctB are EUO-regulated genes; glgA, ctl305, and ctl397 are Pgp4 target genes that do not appear to be regulated by EUO; and groEL is regulated by neither EUO nor Pgp4. For each time point, transcript levels were normalized to the number of chlamydial genomes, as measured by qPCR. Three independent experiments were performed, and transcript copy number/chlamydia was calculated for each gene from the mean of the three replicates. Error bars represent standard deviation. Asterisks indicate statistically significant increases in transcription for the Δpgp4 strain compared to its parental strain (*, P < 0.05; **, P < 0.01).