DnaA as a Transcription Regulator

Abstract

This chapter reviews that DnaA is a transcription factor involved in the regulation of several E. Coli genes. DnaA can act as a repressor or it can be a transcriptional activator. DnaA might terminate transcription, provided two suitably located DnaA boxes mediate loop formation of the template. The transcription regulator function of DnaA is not essential for survival, as dnaA mutants where the replication defect suppressed, is viable. The chapter also discusses the simple and reliable genetic methods that are available for a preliminary analysis whether DnaA regulates a promoter. The easiest way to obtain indications for a regulation by DnaA is to measure the change in expression level of a given gene in a dnaA mutant on a temperature shift. All activities of DnaA, including its role as a transcription regulator, require binding to its cognate-binding site. For a detection of DnaA binding, the same techniques are applied that are generally used for DNA-binding proteins. The oldest method is filter binding, such as binding of a radioactive DNA or oligonucleotide to a nitrocellulose filter via a DnaA protein.