Additional regulatory activities of MrkH for the transcriptional expression of the Klebsiella pneumoniae mrk genes: Antagonist of H-NS and repressor
Por:
Ares, Miguel A., Fernandez-Vazquez, Jose L., Pacheco, Sabino, Martinez-Santos, Veronica I., Dolores Jarillo-Quijada, Ma., Torres, Javier, Alcantar-Curiel, Maria D., Gonzalez-y-Merchand, Jorge A., De la Cruz, Miguel A.
Publicada:
9 mar 2017
Resumen:
Klebsiella pneumoniae is a common opportunistic pathogen causing
nosocomial infections. One of the main virulence determinants of K.
pneumoniae is the type 3 pilus (T3P). T3P helps the bacterial
interaction to both abiotic and biotic surfaces and it is crucial for
the biofilm formation. T3P is genetically organized in three
transcriptional units: the mrkABCDF polycistronic operon, the mrkHI
bicistronic operon and the mrkJ gene. MrkH is a regulatory protein
encoded in the mrkHI operon, which positively regulates the mrkA pilin
gene and its own expression. In contrast, the H-NS nucleoid protein
represses the transcriptional expression of T3P. Here we reported that
MrkH and H-NS positively and negatively regulate mrkJ expression,
respectively, by binding to the promoter of mrkJ. MrkH protein
recognized a sequence located at position -63.5 relative to the
transcriptional start site of mrkJ gene. Interestingly, our results show
that, in addition to its known function as classic transcriptional
activator, MrkH also positively controls the expression of mrk genes by
acting as an anti-repressor of H-NS; moreover, our results support the
notion that high levels of MrkH repress T3P expression. Our data provide
new insights about the complex regulatory role of the MrkH protein on
the transcriptional control of T3P in K. pneumoniae.
Filiaciones:
Ctr Med Nacl Siglo XXI IMSS, Hosp Pediat, Unidad Invest Med Enfermedades Infecciosas & Para, Ciudad De Mexico, Mexico
Inst Politecn Nacl, Escuela Nacl Ciencias Biol, Dept Microbiol, Ciudad De Mexico, Mexico
Univ Nacl Autonoma Mexico, Fac Med, Unidad Invest Med Expt, Ciudad De Mexico, Mexico
Univ Nacl Autonoma Mexico, Inst Biotecnol, Dept Microbiol Mol, Cuernavaca, Morelos, Mexico
Univ Autonoma Guerrero, Unidad Acad Ciencias Quim Biol, Chilpancingo, Guerrero, Mexico
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