Fig. 4

Transciptional analyses showing that the PEP-CTERM gene pepA was regulated by the RpoN1 sigma factor. Bacteria were cultivated at 28 °C in the R2A medium with shaking (200 rpm). The data represent the samples collected at 8 h, 16 h and 24 h. A Transcription of the pepA gene was examined by semi-quantitative RT-PCR with 16S rRNA gene as the loading control. B Trace quantity plotting using ‘Quantity One’ software. The experiments were performed in triplicate. C Transcription of the gene was examined by real-time PCR, relative transcript levels were calculated according to the 2^−ΔΔCt method, 16S rRNA was analyzed and used as an internal control gene. The experiments were performed in triplicate. Error bars represent the standard deviation. D Determination of the transcriptional start site (TSS) of the pepA gene in A. tertiaricarbonis RN12 strain. The blue sequence is the open reading frame of pepA and the arrow-pointed nucleotide G is the determined transcriptional start site (+ 1). The shadowed sequences TGGCAC and CTGCTT are the putative − 24 and − 12 motifs of the promoter recognized by the sigma factor RpoN1