gene regulation
Research Article | Molecular Biology and PhysiologyComplex Multilevel Control of Hemolysin Production by Uropathogenic Escherichia coliUropathogenic E. coli (UPEC) is the major cause of urinary tract infections and a frequent cause of sepsis. Nearly half of all UPEC strains produce the potent cytotoxin hemolysin, and its expression is associated with enhanced virulence. In this study, we explored hemolysin variation within the globally dominant UPEC ST131 clone, finding that strains from the ST131...
Research Article | Host-Microbe BiologyEndogenous Retrovirus-Derived Long Noncoding RNA Enhances Innate Immune Responses via Derepressing RELA ExpressionEndogenous retroviruses are transposable genetic elements comprising 8% to 10% of the human and mouse genomes. Although most ERVs have been inactivated due to deleterious mutations, some are still transcribed. However, the biological functions of transcribed ERVs are largely unknown. Here, we identified a full-length ERV-derived lncRNA, designated lnc-EPAV, as a positive regulator of host innate immune responses. We found that silencing...
Research Article | Host-Microbe BiologyRocA Binds CsrS To Modulate CsrRS-Mediated Gene Regulation in Group A StreptococcusBacterial two-component regulatory systems, comprising a membrane-bound sensor kinase and cytosolic response regulator, are critical in coordinating the bacterial response to changing environmental conditions. More recently, auxiliary regulators which act to modulate the activity of two-component systems, allowing integration of multiple signals and fine-tuning of bacterial responses, have been identified. RocA is a regulatory protein...
Research Article | Molecular Biology and PhysiologyEvidence that Ergosterol Biosynthesis Modulates Activity of the Pdr1 Transcription Factor in Candida glabrataA likely contributor to the increased incidence of non-albicans candidemias involving Candida glabrata is the ease with which this yeast acquires azole resistance, in large part due to induction of the ATP-binding cassette transporter-encoding gene CDR1. Azole drugs lead to induction of Pdr1 transactivation, with a central model being that this...
Research Article | Molecular Biology and PhysiologyThe Evolution of SlyA/RovA Transcription Factors from Repressors to Countersilencers in EnterobacteriaceaeBacteria primarily evolve via horizontal gene transfer, acquiring new traits such as virulence and antibiotic resistance in single transfer events. However, newly acquired genes must be integrated into existing regulatory networks to allow appropriate expression in new hosts. This is accommodated in part by the opposing mechanisms of xenogeneic silencing and countersilencing. An understanding of these mechanisms is necessary to...
Research Article | Molecular Biology and PhysiologyQuorum Sensing Signal Selectivity and the Potential for Interspecies Cross TalkSpecific recognition of cognate signals is considered fundamental to cell signaling circuits as it creates fidelity in the communication system. In bacterial quorum sensing (QS), receptor specificity ensures that bacteria cooperate only with kin. There are examples, however, of QS receptors that respond promiscuously to multiple signals. “Eavesdropping” by these promiscuous receptors can be beneficial in both interspecies competition...
Research Article | Molecular Biology and PhysiologyA Small Regulatory RNA Controls Cell Wall Biosynthesis and Antibiotic ResistanceThe alphaproteobacterium Agrobacterium tumefaciens is able to infect various eudicots causing crown gall tumor formation. Based on its unique ability of interkingdom gene transfer, Agrobacterium serves as a crucial biotechnological tool for genetic manipulation of plant cells. The presence of...
- Research ArticlePhosphotyrosine-Mediated Regulation of Enterohemorrhagic Escherichia coli Virulence
Enterohemorrhagic Escherichia coli (EHEC) causes outbreaks of hemorrhagic colitis and the potentially fatal hemolytic-uremic syndrome. Successful host colonization by EHEC relies on the ability to coordinate the expression of virulence factors in response to environmental cues. A complex network that integrates environmental signals at multiple regulatory levels tightly controls virulence gene expression. We demonstrate that...