NagRBt Is a Pleiotropic and Dual Transcriptional Regulator in Bacillus thuringiensis

Abstract

NagR, belonging to the GntR/HutC family, is a negative regulator that directly represses the nagP and nagAB genes, which are involved in GlcNAc transport and utilization in Bacillus subtilis. Our previous work confirmed that the chitinase B gene (chiB) of Bacillus thuringiensis strain Bti75 is also negatively controlled by YvoABt, the ortholog of NagR from B. subtilis. In this work, we investigated its regulatory network in Bti75 and found that YvoABt is an N-acetylglucosamine utilization regulator primarily involved in GlcNAc catabolism; therefore YvoABt is renamed as NagRBt. The RNA-seq data revealed that 27 genes were upregulated and 14 genes were downregulated in the ΔnagR mutant compared with the wild-type strain. The regulon (exponential phase) was characterized by RNA-seq, bioinformatics software, electrophoretic mobility shift assays, and quantitative real-time reverse transcription PCR. In the Bti75 genome, 19 genes that were directly regulated and 30 genes that were indirectly regulated by NagRBt were identified. We compiled in silico, in vitro, and in vivo evidence that NagRBt behaves as a repressor and activator to directly or indirectly influence major biological processes involved in amino sugar metabolism, nucleotide metabolism, fatty acid metabolism, phosphotransferase system, and the Embden–Meyerhof–Parnas pathway.

Chitinases of Bacillus thuringiensis: Phylogeny, Modular Structure, and Applied Potentials

“…Deletion of the CcpA regulator increases chitinase gene expression and enzyme activity by ∼39-fold (Jiang et al, 2015). Based on previously reports (Deutscher et al, 2006;Xie et al, 2012;Jiang et al, 2015;Cao et al, 2018), we have depicted a model for the regulation mediated by cre/CcpA and dre/NagR B in Figure 4.…”

“…YVoABt complexes with the phosphoprotein Hprser 45 -P to bind to dre (Jiang et al, 2015) thereby repressing expression of the chitinase gene. However, when the bacterium utilizes chitin as a substrate, GlcNAc or oligosaccharides derived from chitin are produced which leads to the displacement of the repressor and subsequent gene transcription (Jiang et al, 2015;Cao et al, 2018). The YVoABt regulator is also known as NagR Bt because it is an ortholog of NagR in B. subtilis.…”

“…The YVoABt regulator is also known as NagR Bt because it is an ortholog of NagR in B. subtilis. NagRBt is a pleiotropic transcriptional regulator that upregulates and downregulates at least 27 and 14 genes, respectively, in B. thuringiensis (Cao et al, 2018).…”

NupR Responding to Multiple Signals Is a Nucleoside Permease Regulator in Bacillus thuringiensis BMB171

“…The samples (BMB171 and BMB171△ nagR2 ) were shipped to Genewiz ( www.genewiz.com ) for mRNA-seq library construction and transcriptome sequencing. As previously described, mRNA-seq library construction, Solexa sequencing, and RNA-seq data analysis were performed ( 4 ).…”

“…Its effector in B. subtilis is glucosamine-6-phosphate (GlcN-6-P) or N -acetylglucosamine-6-phosphate (GlcNAc-6-P), which could abolish its binding to the target gene ( 2 , 3 ). In Bacillus thuringiensis , besides GlcNAc transport and utilization, NagR regulates the expression of chitinase and chitin-binding protein involved in the chitinase degradation ( 4 ). In addition, GlcNAc is an effector of NagR in B. thuringiensis , which is in agreement with NagR in B. subtilis ( 5 ).…”