Genetic complementation and enzyme assays have shown that the DNA region between panF, which encodes pantothenate permease, and orf1, the first gene of the fis operon, encodes prmA, the genetic determinant for the ribosomal protein L11 methyltransferase. Sequencing of this region identified one long open reading frame that encodes a protein of 31,830 Da and corresponds to the prmA gene. We found, both in vivo and in vitro, that prmA is expressed from promoters located upstream of panF and thus that the panF and prmA genes constitute a bifunctional operon. We located the major 3' end of prmA transcripts 90 nucleotides downstream of the stop codon of prmA in the DNA region upstream of the fis operon, a region implicated in the control of the expression of the fis operon. Although no promoter activity was detected immediately upstream of prmA, S1 mapping detected 5' ends of mRNA in this region, implying that some mRNA processing occurs within the bicistronic panF-prmA mRNA.
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http://dx.doi.org/10.1128/jb.175.22.7178-7188.1993 | DOI Listing |
Unlabelled: The capsular polysaccharide synthesis ( ) locus of is implicated in invasive meningococcal disease. The synthesis ( ) and transport ( ) operons are transcribed in opposite directions from a common intergenic region and expression is negatively regulated by the bacterial two-component system and thermosensitive RNA folding. However, these mechanisms do not fully explain the stationary phase responses and the cis-acting elements remain to be fully characterized.
View Article and Find Full Text PDFMicrobiology (Reading)
January 2023
Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin, Ireland.
The structural genes expressing type 1 fimbriae in alternate between expressed (phase ON) and non-expressed (phase OFF) states due to inversion of the 314 bp genetic switch. The FimB tyrosine integrase inverts by site-specific recombination, alternately connecting and disconnecting the operon encoding the fimbrial subunit protein and its associated secretion and adhesin factors, to and from its transcriptional promoter within . Site-specific recombination by the FimB recombinase becomes biased towards phase ON as DNA supercoiling is relaxed, a condition that occurs when bacteria approach the stationary phase of the growth cycle.
View Article and Find Full Text PDFJ Bacteriol
January 2023
Department of Microbiology, University of Georgia, Athens, Georgia, USA.
The adaptation of Salmonella enterica serovar Typhimurium to stress conditions involves expression of genes within the regulon of the alternative sigma factor RpoN (σ). RpoN-dependent transcription requires an activated bacterial enhancer binding protein (bEBP) that hydrolyzes ATP to remodel the RpoN-holoenzyme-promoter complex for transcription initiation. The bEBP RtcR in Typhimurium strain 14028s is activated by genotoxic stress to direct RpoN-dependent expression of the RNA repair operon The molecular signal for RtcR activation is an oligoribonucleotide with a 3'-terminal 2',3'-cyclic phosphate.
View Article and Find Full Text PDFFront Plant Sci
October 2022
Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.
Phytopathogen is a causal agent of rice foot rot disease and the pathogen has an array of virulence factors, such as phytotoxin zeamines, plant cell wall degrading enzymes, cell motility, and biofilms, collectively contributing to the bacterial pathogenesis. In this study, through deletion analysis of predicted regulatory genes in EC1, we identified a two-component system associated with the regulation of bacterial virulence. The two-component system contains a histidine kinase ArcB and a response regulator ArcA, and deletion of their coding genes resulted in changed phenotypes in cell motility, biofilm formation, and bacterial virulence.
View Article and Find Full Text PDFInt J Mol Sci
September 2022
School of Biological Sciences, Department of Molecular Biology, University of California-San Diego, La Jolla, CA 92093, USA.
Using reporter gene () transcriptional fusions we examined the transcriptional dependencies of the promoter (P) and the entire operon regulatory region (P-) on eight transcription factors as well as the inducer, salicin, and an IS5 insertion upstream of P. Crp-cAMP is the primary activator of both P and the operon, while H-NS is a strong dominant operon repressor but only a weak repressor of P. H-NS may exert its repressive effect by looping the DNA at two binding sites.
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