According to a recent study published in the online journal of the American Society for Microbiology, researchers from University of Texas Southwestern Medical School suggested that two small RNAs have the capacity to allow the pathogenic strain of enterohemorrhagic Escherichia coli (EHEC) to invade and infect the lining cells of the gut and cause disease.
E-coli strain EHEC is classified under gram-negative pathogens that invade the host tissue with the help of a special system of protein secretions (also known as type III secretion systems or T3SS) that helps in cytoskeletal reorganization of bacteria in host tissues, thereby serving as docking stations for adhesion and invasion.
The latest research conducted by a research team at UT Southwestern in Dallas has helped in shedding some light on the complex and effective system of bacterial coordination in the formation of T3SS formation and pedestal formation. Vanessa Sperandio, Charley Gruber and their associates at the UT Southwestern suggested that the intricate and precise coordination of bacterial genes involve locus of enterocytes effacement (LEE) — the pathogenicity islands that are in turn orchestrated by GlmZ and GlmY. The two small RNAs GlmZ and GlmY provide the driving force that allows EHEC to invade mammalian cells, as explained by Dr. Sperandio in the report. She suggested that the two small RNAs act together to cleave the chain of transcription between two important genes, espFu and espJ. The resulting effect is the formation of invasion protein EspFu. Additionally, the two small RNAs help in the destabilization of important transcripts like LEE 4 and 5 that further fine-tune genetic expression of
Sperandio further explained that the LEE destabilization process is important because:
– It allows different genes to express individually besides being encoded as part of the same cluster.
– In the setting of an infection, LEE destabilization ensure the formation of optimal pedestal levels on the lining cells.
The research team proposed that the two small RNA molecules are responsible for the re-wiring of the complicated bacterial machinery.
Recognition by other researchers:
The UT Southwestern researchers’s findings have received recognition and appreciation on both a national and international level. École Polytechnique Fédérale de Lausanne, Switzerland-based researcher Petr G. Leiman suggested that the discovery is indeed a great contribution to the field of science. Leiman also added that the research on sRNA is fairly difficult and requires controls that are evident in the report presented by Sperandio and her colleagues. In the report, UT Southwestern scientists also explained the complicated interplay of evolution of EHEC genes adding to the virulence factor.
Photos from wikipedia.org, UT Southwestern