The transcription of cts genes in these mutants examined by reverse transcriptase PCR (RT-PCR) was consistent with the infection recovery in Fig. 2; cbp mRNA was detected in NIID84 Δcps, HT2080, and HT2077, in which only the cbp gene was complemented, but ctp and cab mRNA were detected only in NIID84 Δcps and HT2080, indicating that the cbp, ctp, and cab genes were transcriptionally comprised of one operon at the cts gene allele (Fig. S2). This evidence concerns the gene TTR and infection.