Genome-wide survey for PilR recognition sites of the metal-reducing prokaryote Geobacter sulfurreducens.
Geobacter sulfurreducens is a species from the bacterial family Geobacteraceae, members of which participate in bioenergy production and in environmental bioremediation. G. sulfurreducens pili are electrically conductive and are required for Fe(III) oxide reduction and for optimal current production in microbial fuel cells. PilR is an enhancer binding protein, which is an activator acting together with the alternative sigma factor, RpoN, in transcriptional regulation. Both RpoN and PilR are involved in regulation of expression of the pilA gene, whose product is pilin, a structural component of a pilus. Using bioinformatic approaches, we predicted G. sulfurreducens sequence elements that are likely to be regulated by PilR. The functional importance of the genome region containing a PilR binding site predicted upstream of the pilA gene was experimentally validated. The predicted G. sulfurreducens PilR binding sites are similar to PilR binding sites of Pseudomonas and Moraxella. While the number of predicted PilR-regulated sites did not deviate from that expected by chance, multiple sites were predicted upstream of genes with roles in biosynthesis and function of pili and flagella, in secretory pathways, and in cell wall biogenesis, suggesting the possible involvement of G. sulfurreducens PilR in regulation of production and assembly of pili and flagella.
Krushkal
Julia
J
Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA. jkrushka@uthsc.edu
Juárez
Katy
K
Barbe
Jose F
JF
Qu
Yanhua
Y
Andrade
Angel
A
Puljic
Marko
M
Adkins
Ronald M
RM
Lovley
Derek R
DR
Ueki
Toshiyuki
T
D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D001665:Binding Sites; D017124:Conserved Sequence; D005290:Ferric Compounds / Q000378:metabolism*; D036781:Fimbriae Proteins / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D016680:Genome, Bacterial; D045302:Geobacter / Q000235:genetics*; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000235:genetics; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D005290:Ferric Compounds; C061338:NifA protein, Bacteria; D014157:Transcription Factors; D036781:Fimbriae Proteins