The DNA-Binding Protein HU has a Regulatory Role in the Acid Stress Response Mechanism in Helicobacter pylori
Author
dc.contributor.author
Almarza, Oscar
Author
dc.contributor.author
Núñez, Daniel
Author
dc.contributor.author
Toledo Araya, Héctor
Admission date
dc.date.accessioned
2015-08-05T18:36:43Z
Available date
dc.date.available
2015-08-05T18:36:43Z
Publication date
dc.date.issued
2015
Cita de ítem
dc.identifier.citation
Helicobacter 20: 29–40
en_US
Identifier
dc.identifier.issn
1523-5378
Identifier
dc.identifier.other
DOI: 10.1111/hel.12171
Identifier
dc.identifier.uri
https://repositorio.uchile.cl/handle/2250/132427
General note
dc.description
Artículo de publicación ISI
en_US
Abstract
dc.description.abstract
Background: Bacterial genomes are compacted by association with histonelike
proteins to form a complex known as bacterial chromatin. The histonelike
protein HU is capable of binding and bending the DNA molecule, a
function related to compaction, protection, and regulation of gene expression.
In Helicobacter pylori, HU is the only histone-like protein described so
far. Proteomic analysis from our laboratory showed that this protein is overexpressed
under acidic stress.
Materials and Methods: We used a purified recombinant wild-type protein
and two mutant proteins with the amino acid substitutions K3A/S27D and
K62R/V63N/P64A to characterize the function of the N-terminal domain
and the flexible arm of HU.
Results: In vitro assays for DNA protection, bending, and compaction were
performed. We also designed a H. pylori hup::cat mutant strain to study the
role of HU in the acid stress response. HUwt protein binds DNA and promotes
its bending and compaction. Compared with the wild-type protein, both
mutant proteins have less affinity for DNA and an impaired bending and
compaction ability. By using qRT-PCR, we confirmed overexpression of
two genes related to acid stress response (ureA and speA). Such overexpression
was abolished in the hup::cat strain, which shows an acid-sensitive
phenotype.
Conclusions: Altogether, we have shown that HUwt–DNA complex formation
is favored under acidic pH and that the complex protects DNA from
endonucleolytic cleavage and oxidative stress damage. We also showed that
the amino-terminal domain of HU is relevant to DNA–protein complex
formation and that the flexible arm of HU is involved in the bending and
compaction activities of HU.
en_US
Patrocinador
dc.description.sponsorship
FONDECYT-Chile
1120126
Universidad de Chile
Enlace ENL 11/07