Figure 1.

In vivo transcription activation of Ptox-gusA fusions by txeR in trans in C. perfringens. Fragments of DNA carrying either toxA (A) or toxB (B) gene promoters were cloned in the reporter fusion vector pTUM177 and introduced into C. perfringens with or without the txeR gene in trans. β-Glucuronidase activity of late stationary phase cells grown in TY or TYG medium was assayed as described previously (7). In control experiments, cells carrying the fusion vector alone were assayed. Solid bars, TY medium, no TxeR; open bars, TYG medium, no TxeR; striped bars, TY medium with TxeR; dotted bars, TYG medium, with TxeR.