TY - JOUR
T1 - FimY of Salmonella enterica serovar Typhimurium functions as a DNA-binding protein and binds the fimZ promoter
AU - Wang, Ke Chuan
AU - Hsu, Yuan Hsun
AU - Huang, Yi Ning
AU - Lin, Jiunn Horng
AU - Yeh, Kuang Sheng
PY - 2014
Y1 - 2014
N2 - Salmonella enterica serovar Typhimurium produces type 1 fimbriae with binding specificity to mannose residues. Elements involved in fimbrial structural biosynthesis, transport, and regulation are encoded by the fim gene cluster. FimZ, FimY, FimW, STM0551, and an arginine transfer RNA (fimU) were previously demonstrated to regulate fimbrial expression. The amino acid sequences of the C-terminal portion of FimY revealed similarity with those of LuxR-like proteins. Electrophoretic mobility shift assays indicated that FimY possessed DNA-binding capacity and bound a 605-bp DNA fragment spanning the intergenic region between fimY and fimZ, while a FimY protein harboring a double mutation in the C-terminal helix-turn-helix region containing a glycine (G) to aspartate (D) substitution at residue 189 and isoleucine (I) to lysine (K) substitution at residue 195 lost its ability to bind this DNA fragment. A lux box sequence (5'-TCTGTTATTACATAACAAATACT-3') within the fimZ promoter was required for binding. None of the DNA fragments derived from the promoters for fimA, fimY, or fimW was shifted by FimY. Pull-down assays showed that there were physical protein/protein interactions between FimY and FimZ. We propose that in the regulatory circuit of type 1 fimbriae, FimY functions as a DNA-binding protein to activate fimZ, and a FimY-FimZ protein complex may form to regulate other fim genes. Confirming these proposals requires further study.
AB - Salmonella enterica serovar Typhimurium produces type 1 fimbriae with binding specificity to mannose residues. Elements involved in fimbrial structural biosynthesis, transport, and regulation are encoded by the fim gene cluster. FimZ, FimY, FimW, STM0551, and an arginine transfer RNA (fimU) were previously demonstrated to regulate fimbrial expression. The amino acid sequences of the C-terminal portion of FimY revealed similarity with those of LuxR-like proteins. Electrophoretic mobility shift assays indicated that FimY possessed DNA-binding capacity and bound a 605-bp DNA fragment spanning the intergenic region between fimY and fimZ, while a FimY protein harboring a double mutation in the C-terminal helix-turn-helix region containing a glycine (G) to aspartate (D) substitution at residue 189 and isoleucine (I) to lysine (K) substitution at residue 195 lost its ability to bind this DNA fragment. A lux box sequence (5'-TCTGTTATTACATAACAAATACT-3') within the fimZ promoter was required for binding. None of the DNA fragments derived from the promoters for fimA, fimY, or fimW was shifted by FimY. Pull-down assays showed that there were physical protein/protein interactions between FimY and FimZ. We propose that in the regulatory circuit of type 1 fimbriae, FimY functions as a DNA-binding protein to activate fimZ, and a FimY-FimZ protein complex may form to regulate other fim genes. Confirming these proposals requires further study.
KW - DNA binding protein
KW - Salmonella
KW - Type 1 fimbriae
UR - http://www.scopus.com/inward/record.url?scp=84899936358&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84899936358&partnerID=8YFLogxK
U2 - 10.1016/j.micres.2013.12.006
DO - 10.1016/j.micres.2013.12.006
M3 - Article
C2 - 24462182
AN - SCOPUS:84899936358
VL - 169
SP - 496
EP - 503
JO - Microbiological Research
JF - Microbiological Research
SN - 0944-5013
IS - 7-8
ER -