Researchers describe a new regulatory mechanism for salmonella virulence with small RNA fragments

June 8, 2018, University of Barcelona
Salmonella enterica is one of the main enteric pathogens in developed countries and underdevelopment areas as well. Credit: Universidad de Barcelona

A series of small RNA fragments are the regulator factors involved in a new control mechanism for salmonella virulence, a pathogenic bacterium which causes bacterial gastroenteritis with a high incidence –more than 100,000 cases per year- in Europe.

The findings of the new regulating mechanism, published in the journal PLOS Genetics, are reported by Carlos Balsalobre, lecturer at the Faculty of Biology of the University of Barcelona, and it means a step forward in the development of new therapeutic strategies to treat infections in the food chain.

According to the study, these small RNA chains could regulate the genic expression of the involved in a key process in 's ability to cause an infection. Other participants of the study are the UB experts Youssef El Mouali, Tania Gaviria Cantín and Marta Gilabert, as well as María Antonia Sánchez-Romero (University of Seville), and Alexander J. Westermann and Jörg Vogel (University of Würzburg, Germany).

Salmonella enterica is one of the main enteric pathogens in developed countries and underdevelopment areas as well. In fact, salmonella is present in domestic and wild animals, and can cross the whole food chain. Regarding humans, most of the cases of salmonella have their origins in the consumption of foods with natural origin that are already infected by the bacterium, and can cause light gastroenteritis and more general severe infections.

During the infection process, S. enterica invades the , a determining process to unchain the , which requires the coordinated expression of a series of genes. According to Carlos Balsalobre, lecturer at the Department of Genetics, Microbiology and Statistics of the UB, "once the we eat the food that is already affected by salmonella, the bacterium gets to the intestine, where it is able to invade epithelial cells, a determining process to unchain the bacterial infection".

Objective: genes from the Salmonella pathogenicity island

Most of the coded genes by involved factors in the invasion of epithelial cells –and determining for the virulent capacity of the bacterium- are grouped in a chromosomal region known as the Salmonella pathogenicity island (SPI-1). For decades, great part of the scientific research has focused on the description of mechanisms that activate the expression of the genes in SPI-1 during the bacterial infectious process.

"However, in this study we focused on the opposite case", adds Balsalobre. "That is, we studied the important factors to keep these genes silent when the bacterium does not need to invade the guest's epithelial cells".

The new study reveals that the CRP-AMPc metabolic sensor is involved in the control of the expression of the genes in the SPI-1. This control occurs at a post-transcriptional level and indirectly, through the regulation of the expression of a small RNA fragment (Spot 42). The mechanism of the regulation, described now for the first time, takes place through the interaction of the small RNA fragments with the terminal region of the corresponding RNA messenger (in particular, with 3'UTR).

This study, a new step towards the knowledge of control mechanisms in bacteria to regulate the genic expression, will contribute to design new therapeutic tools to work on one of the microorganisms that shows a higher resistance to the use of antimicrobials.

Explore further: A new machine learning tool could flag dangerous bacteria before they cause an outbreak

More information: Youssef El Mouali et al. CRP-cAMP mediates silencing of Salmonella virulence at the post-transcriptional level, PLOS Genetics (2018). DOI: 10.1371/journal.pgen.1007401

Related Stories

A new machine learning tool could flag dangerous bacteria before they cause an outbreak

May 8, 2018
A new machine learning tool that can detect whether emerging strains of the bacterium, Salmonella are more likely to cause dangerous bloodstream infections rather than food poisoning has been developed. The tool, created ...

Recommended for you

Study reveals broad 'genetic architectures' of traits and diseases

August 13, 2018
Scientists at Johns Hopkins Bloomberg School of Public Health have developed a powerful method for characterizing the broad patterns of genetic contributions to traits and diseases. The new method provides a "big picture" ...

Researchers predict risk for common deadly diseases from millions of genetic variants

August 13, 2018
A research team at the Broad Institute of MIT and Harvard, Massachusetts General Hospital (MGH), and Harvard Medical School reports a new kind of genome analysis that could identify large fractions of the population who have ...

Genetic tools uncover cause of childhood seizure disorder missed by other methods

August 13, 2018
Early childhood seizures result from a rare disease that begin in the first months of life. Researchers at University of Utah Health have developed high-tech tools to uncover the genetic cause of the most difficult to diagnose ...

Evolutionary changes in the human brain may have led to bipolar disorder and schizophrenia

August 9, 2018
The same aspects of relatively recent evolutionary changes that make us prone to bad backs and impacted third molars may have generated long, noncoding stretches of DNA that predispose individuals to schizophrenia, bipolar ...

Genetic mutation underlying severe childhood brain disorder identified

August 9, 2018
Ashleigh Schaffer, Ph.D., assistant professor of genetics at Case Western Reserve University School of Medicine, and a team of global genetics experts have discovered a genetic mutation and the faulty development process ...

Unexpected outcomes sound warning for treatment of genetic diseases using gene editing in embryos

August 9, 2018
New research led by the South Australian Health and Medical Research Institute (SAHMRI) and the University of Adelaide has uncovered a significant hurdle for realising the potential benefits of gene editing in embryos.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.