TY - JOUR
T1 - A trans-acting leader RNA from a Salmonella virulence gene
AU - Choi, Eunna
AU - Han, Yoontak
AU - Cho, Yong Joon
AU - Nam, Daesil
AU - Lee, Eun Jin
N1 - Funding Information:
ACKNOWLEDGMENTS. This work was supported, in part, by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, Information and Communications Technology, and Future Planning (NRF-2013R1A1A2074505 and NRF-2016R1A2B2012424) (to E.-J.L.).
Publisher Copyright:
© 2017, National Academy of Sciences. All rights reserved.
PY - 2017/9/19
Y1 - 2017/9/19
N2 - Bacteria use flagella to move toward nutrients, find its host, or retract from toxic substances. Because bacterial flagellum is one of the ligands that activate the host innate immune system, its synthesis should be tightly regulated during host infection, which is largely unknown. Here, we report that a bacterial leader mRNA from the mgtCBR virulence operon in the intracellular pathogen Salmonella enterica serovar Typhimurium binds to the fljB coding region of mRNAs in the fljBA operon encoding the FljB phase 2 flagellin, a main component of bacterial flagella and the FljA repressor for the FliC phase 1 flagellin, and degrades fljBA mRNAs in an RNase E-dependent fashion during infection. A nucleotide substitution of the fljB flagellin gene that prevents the mgtC leader RNA-mediated down-regulation increases the fljB-encoded flagellin synthesis, leading to a hypermotile phenotype inside macrophages. Moreover, the fljB nucleotide substitution renders Salmonella hypervirulent, indicating that FljB-based motility must be compromised in the phagosomal compartment where Salmonella resides. This suggests that this pathogen promotes pathogenicity by producing a virulence protein and limits locomotion by a trans-acting leader RNA from the same virulence gene during infection.
AB - Bacteria use flagella to move toward nutrients, find its host, or retract from toxic substances. Because bacterial flagellum is one of the ligands that activate the host innate immune system, its synthesis should be tightly regulated during host infection, which is largely unknown. Here, we report that a bacterial leader mRNA from the mgtCBR virulence operon in the intracellular pathogen Salmonella enterica serovar Typhimurium binds to the fljB coding region of mRNAs in the fljBA operon encoding the FljB phase 2 flagellin, a main component of bacterial flagella and the FljA repressor for the FliC phase 1 flagellin, and degrades fljBA mRNAs in an RNase E-dependent fashion during infection. A nucleotide substitution of the fljB flagellin gene that prevents the mgtC leader RNA-mediated down-regulation increases the fljB-encoded flagellin synthesis, leading to a hypermotile phenotype inside macrophages. Moreover, the fljB nucleotide substitution renders Salmonella hypervirulent, indicating that FljB-based motility must be compromised in the phagosomal compartment where Salmonella resides. This suggests that this pathogen promotes pathogenicity by producing a virulence protein and limits locomotion by a trans-acting leader RNA from the same virulence gene during infection.
KW - Flagellin
KW - Trans-acting leader RNA
KW - mgtC
UR - http://www.scopus.com/inward/record.url?scp=85029548583&partnerID=8YFLogxK
U2 - 10.1073/pnas.1705437114
DO - 10.1073/pnas.1705437114
M3 - Article
C2 - 28874555
AN - SCOPUS:85029548583
SN - 0027-8424
VL - 114
SP - 10232
EP - 10237
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 38
ER -