Insight into the molecular and functional determinants of HP1043, the essential master regulator of Helicobacter pylori.

Zannoni, Annamaria (2021) Insight into the molecular and functional determinants of HP1043, the essential master regulator of Helicobacter pylori., [Dissertation thesis], Alma Mater Studiorum Università di Bologna. Dottorato di ricerca in Biologia cellulare e molecolare, 33 Ciclo. DOI 10.48676/unibo/amsdottorato/9840.
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Helicobacter pylori is one of the most widespread and successful human pathogens, colonizing half of the population stomach mucosa and causing gastric malignancies in 1% of carriers. Due to the increasing number of antimicrobial-resistant strains, in 2017 the WHO included H. pylori among pathogens that pose a major threat for humankind. In this study, we propose as a molecular target for novel antimicrobial strategies HP1043, an orphan response regulator essential for the viability of H. pylori as it orchestrates all the most important cellular processes. Amino acids most relevant for HP1043 dimerization and target DNA recognition were identified and used to guide an in-silico protein-DNA docking and generate a high-resolution structural model of the interacting HP1043 dimer and its target DNA. The model was experimentally validated and exploited to carry out a virtual screening of small molecule libraries, identifying 8 compounds potentially able to interfere with HP1043 function and likely block H. pylori infection. A second line of research aimed at the characterization of the regulatory function of HP1043 and the tight mechanisms of regulation of hp1043 gene expression. In particular, we proved a direct interaction between HP1043 and the housekeeping sigma80 factor of the RNA polymerase. A conditional mutant H. pylori strain overexpressing a synthetic copy of the hp1043 gene altered in nucleotide sequence yet encoding the wild-type protein was generated, achieving increased intracellular levels of HP1043. However, overexpression of HP1043 did not result in an upregulation of target genes transcription nor modulation of hp1043 transcript levels, pinpointing the existence of multiple overlayed mechanisms of regulation that affect both protein levels and functionality as well as maintain steady the amount of hp1043 transcript. Finally, we proposed that a mechanism of post-transcriptional regulation could depend on an antisense transcript to the hp1043 gene which was validated in two different strains.

Tipologia del documento
Tesi di dottorato
Zannoni, Annamaria
Dottorato di ricerca
Settore disciplinare
Settore concorsuale
Parole chiave
Helicobacter pylori, HP1043, transcriptional regulation
Data di discussione
10 Giugno 2021

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