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Shigella

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Full-Text Articles in Molecular Biology

Transcriptional Control Of Virulence Genes In The Bacterial Pathogen Shigella Flexneri, Joy Asami Mckenna Aug 2020

Transcriptional Control Of Virulence Genes In The Bacterial Pathogen Shigella Flexneri, Joy Asami Mckenna

UNLV Theses, Dissertations, Professional Papers, and Capstones

Shigella species, the causal agents of bacillary dysentery, use a type III secretion system (T3SS) to inject two waves of virulence proteins, known as effectors, into the human colonic epithelium to subvert host cell machinery. Transcriptional regulation of these virulence genes is controlled by the three-tiered VirF/VirB/MxiE signaling cascade. Of these, VirB has the largest regulon (~50 genes); however, VirB regulatory properties are poorly understood. To date, VirB is known to function to counter or 'anti-silence' transcriptional silencing mediated by the histone-like nucleoid structuring protein H-NS. To better understand VirB regulation, my colleagues and I chose to better define the …


Transcriptional Silencing And Anti-Silencing Of Virulence Genes In The Bacterial Pathogen Shigella Flexneri: Virb, Dna Supercoiling, And The Histone-Like Nucleoid Structuring Protein, Michael Adam Picker May 2018

Transcriptional Silencing And Anti-Silencing Of Virulence Genes In The Bacterial Pathogen Shigella Flexneri: Virb, Dna Supercoiling, And The Histone-Like Nucleoid Structuring Protein, Michael Adam Picker

UNLV Theses, Dissertations, Professional Papers, and Capstones

Transcriptional silencing and anti-silencing affect many aspects of bacterial physiology, including virulence in bacterial pathogens. In Shigella species, a group of gram-negative pathogens that cause bacillary dysentery in humans, the histone-like nucleoid structuring protein (H-NS) transcriptionally silences virulence genes found on the large virulence plasmid while VirB anti-silences these genes. However, the mechanistic details of their interplay are not fully understood. To elucidate their regulatory mechanisms, I use the icsP virulence locus, which shares a long intergenic region with the divergently transcribed ospZ gene (1535 bp from TSS to TSS). Prior to this work, two discrete H-NS binding regions had …