Analysis of the sfaXII locus in the Escherichia coli meningitis isolate IHE3034 reveals two novel regulatory genes within the promoter-distal region ofthe main S fimbrial operon
2009 (English)In: Microbial Pathogenesis, ISSN 0882-4010, E-ISSN 1096-1208, Vol. 46, no 3, 150-158 p.Article in journal (Refereed) Published
We describe the expression and regulation of the gene sfaXII located near the SfaII fimbrial determinant inthe newborn meningitis Escherichia coli (NMEC) isolate IHE3034. sfaXII belongs to a gene family, the 17-kDa genes, typically located downstream (300–3000 bp) of different fimbrial operons found in E. coli isolates of uropathogenic and newborn meningitis origin. Using transcriptional sfaXII reporter genefusions we found that different environmental conditions commonly affecting expression of fimbrialgenes also affected sfaXII expression. Analysis of the sfaXII transcripts showed that the gene is part of themain fimbrial operon as it is transcribed together with the rest of the fimbrial genes. In addition, the sfaXII gene can be expressed from a more proximal promoter and is found to be subject to strong downregulationby the nucleoid protein H-NS. Studies with an sfaXII mutant derivative of IHE3034 did notreveal effects on SfaII fimbrial biogenesis as monitored by e.g. immunofluorescence microscopy. Nevertheless,a mutation in sfaXII resulted in altered expression of other surface components. Moreover, we define a new gene, sfaYII, coding for a putative phosphodiesterase that is located in between the sfaXII gene and the fimbrial biogenesis genes. Our studies by ectopic expression of sfaYII in Vibrio cholerae showed that the gene product caused reduced biofilm formation and it is proposed that sfaYII caninfluence cyclic-di-GMP turnover in the bacteria. Our findings demonstrate that the operons typical for S-fimbriae of extraintestinal pathogenic E. coli include previously unrecognized novel regulatory genes.
Place, publisher, year, edition, pages
Elsevier Ltd , 2009. Vol. 46, no 3, 150-158 p.
NMEC, Regulation, Fimbrial genes, sfa operon
Biochemistry and Molecular Biology
Research subject Molecular Biology
IdentifiersURN: urn:nbn:se:umu:diva-114402OAI: oai:DiVA.org:umu-114402DiVA: diva2:895185