Mutants lacking flagella are highly attenuated in animal models ( Guerry, 2007). jejuni as they are required for pathogenicity-related phenotypes including colonization ( Wassenaar et al., 1993), interactions with host cells ( Guerry, 2007 Freitag et al., 2017), biofilm formation ( Svensson et al., 2014), and the secretion of virulence-associated proteins such as Cia invasion antigens ( Konkel et al., 1999). Flagella are well-characterized virulence factors in C. jejuni must accommodate a range of stresses such as changes in temperature, pH, oxygen level, and exposure to host bile, digestive enzymes, and inflammatory responses. To survive in diverse hosts and environmental niches, C. However, exposure to environmental sources such as surface waters is suggested to cause a large proportion of Campylobacter infections ( Champion et al., 2005). Therefore, the source of infection is often the consumption of contaminated meat (especially poultry) or drinking of contaminated raw milk ( Kaakoush et al., 2015). jejuni commensally colonizes the gastrointestinal tract of animals including poultry, cattle, swine, and sheep ( Kaakoush et al., 2015). jejuni infection is generally acute and self-limiting, but in some patients it is associated with the development of post-infection sequelae such as autoimmune-mediated Guillain-Barré Syndrome, the leading cause of acute paralysis ( Nachamkin et al., 2000). Symptoms typically consist of 4–7 days of severe watery to bloody diarrhea, abdominal cramping, fever, vomiting, and dehydration ( Kaakoush et al., 2015). The majority of the amino acids implicated in RNA binding were conserved among diverse Campylobacter species.Ĭampylobacter jejuni is a leading bacterial cause of foodborne gastroenteritis throughout the world ( WHO, 2015), with 1.3 million cases of Campylobacter infections in the US ( Tack et al., 2019) and 96 million cases globally each year ( WHO, 2013). Decreased flaA mRNA binding by mutant CsrA proteins L2A and A36V was confirmed by electrophoretic mobility shift assays. These assays allowed us to identify 19 amino acids that were involved in RNA binding by CsrA, with many but not all of these amino acids clustered in predicted beta strands that are involved in RNA binding by E. jejuni CsrA and assessed the regulatory activity of these mutant proteins, using a reporter system encoding the 5′ untranslated region (5′ UTR) upstream of flaA linked translationally to the C. We performed saturating site-directed mutagenesis on C. In this study, we used in vitro SELEX to identify the consensus RNA sequence mAwGGAs to which C. jejuni CsrA that are critical for RNA binding. jejuni CsrA is significantly different from that of Escherichia coli CsrA, and no previous research has defined the amino acids of C. Additionally, CsrA has previously been shown to regulate 120–150 proteins involved in diverse cellular processes. The post-transcriptional regulator CsrA regulates the expression of the major flagellin FlaA by binding to flaA mRNA and repressing its translation. jejuni, as these organelles are required for pathogenicity-related phenotypes including motility, biofilm formation, host cell interactions, and host colonization. Flagella are considered a primary virulence factor in C. jejuni is a leading cause of foodborne gastroenteritis, and these infections are sometimes associated with the development of post-infection sequelae such as Guillain-Barré Syndrome. Division of Infectious Diseases, Department of Medicine, Augusta University, Augusta, GA, United StatesĬampylobacter jejuni is a Gram-negative rod-shaped bacterium that commensally inhabits the intestinal tracts of livestock and birds, and which also persists in surface waters.
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