An Atlas of Pseudomonas genes

HZI scientists identify the regulons of the most important sigma factors of Pseudomonas aeruginosa

18.03.2015

"Genome atlas" of the sigma factors of Pseudomonas aeruginosa

©HZI/Häußler

Certain proteins play a crucial role in the processing of genetic information by bacteria: The so-called sigma factors are responsible for the start of transcription, i.e. the process of making RNA from DNA. Recently, Scientists of the Helmholtz Centre for Infection Research (HZI) in Braunschweig were the first to describe the group of genes regulated by the most important sigma factors of the Pseudomonas aeruginosa pathogen. The results published in "PLOS Pathogens" provide important insights into the stress responses of the bacterium and its virulence. In the long-term, this may help identify sites of attack for medications against this pathogen.

Pseudomonas aeruginosa is a much-feared cause of hospital-acquired infections, which are also called nosocomial infections and can have a severe and often even fatal outcome. The pathogen is also common in persons suffering from burn injuries and in the lung of cystic fibrosis patients. These bacteria possess a remarkable ability to adapt and survive even under extreme conditions. "It is important to know exactly how they survive these stress conditions and which genes facilitate their adaptation to find starting points for possible therapies," says Prof Susanne Häußler, head of the Molecular Bacteriology department at the HZI. The so-called sigma factors are the key to this information: These proteins play a crucial role in the conversion of genetic information.

 "Using modern technologies, we were the first to successfully describe the ten most important sigma factors of Pseudomonas aeruginosa and to assign genes to them," says Häußler.  This work allowed Häußler and her colleagues to produce an unprecedented "genome atlas" of the sigma factors of Pseudomonas. They published the atlas on a freely accessible server on the internet such that the results are available to scientists throughout the world. "This is a new way of publishing results that will benefit the work of many microbiologists," says Häußler.

The new insights allow the researchers to investigate the interaction of sigma factors with other transcription factors and to obtain answers about the mechanisms used in the adaptation to complex environmental conditions. "Once we know which sigma factors are responsible for which genes, we can derive information about the function of yet unknown genes," says Dr Denitsa Eckweiler, who co-authored the study.

Important information in the search for approaches to new therapies in the long-term.

Original publication:

Schulz S, Eckweiler D, Bielecka A, Nicolai T, Franke R, et al. (2015) Elucidation of Sigma Factor-Associated Networks in Pseudomonas aeruginosa Reveals a Modular Architecture with Limited and Function-Specific Crosstalk. PLoS Pathog 11(3): e1004744. DOI:10.1371/journal.ppat.1004744.