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Functions of the Hha and YdgT Proteins in Transcriptional Silencing by the Nucleoid Proteins, H-NS and StpA, in Escherichia coli

2013; University of Oxford; Volume: 20; Issue: 3 Linguagem: Inglês

10.1093/dnares/dst008

1756-1663

Takeshi Ueda, Hiro Takahashi, Ebru Uyar, Shu Ishikawa, Naotaka Ogasawara, Taku Oshima,

CRISPR and Genetic Engineering

The Hha and YdgT proteins are suggested to modulate the expression of horizontally acquired genes by interacting with H-NS and StpA, which play central roles in the transcriptional silencing of such genes. However, it is also possible that Hha/YdgT repress gene expression independently of H-NS/StpA, as we have not fully understood the molecular mechanism through which Hha/YdgT modulate H-NS/StpA activity. To gain further insight into the basic functions of Hha/YdgT, we analysed the impact of hha/ydgT double inactivation on the transcriptome profile of Escherichia coli K-12, and compared the effects with that of hns/stpA double inactivation. In addition, we examined the effects of hha/ydgT inactivation on the chromosomal binding of H-NS, and conversely the effects of hns/stpA inactivation on the chromosomal binding of Hha. Our results demonstrated that the chromosomal binding of Hha requires H-NS/StpA, and is necessary for the repression of a subset of genes in the H-NS/StpA regulon. Furthermore, the distribution of H-NS binding around Hha/YdgT-dependent and -independent genes suggests that Hha/YdgT proteins modulate formation of the H-NS/StpA-DNA complex.