Here, we sought to clarify the role of TcdC in regulation of the toxin production by generating an isogenic tcdC mutant (CT::tcdC) using the ClosTron technology. We find only minor differences in transcription levels of the PaLoc genes between the wild type and CT::tcdC strains and the expressed total toxin levels did not significantly differ, suggesting that the role of TcdC in toxin regulation is not of significance under the conditions tested in C. difficile strain 630DErm.