Publications by authors named "P Polard"
Homologous recombination (HR) is a universally conserved mechanism of DNA strand exchange between homologous sequences, driven in bacteria by the RecA recombinase. HR is key for the maintenance of bacterial genomes via replication fork restart and DNA repair, as well as for their plasticity via the widespread mechanism of natural transformation. Transformation involves the capture and internalization of exogenous DNA in the form of single strands, followed by HR-mediated chromosomal integration.
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- Some DNA helicases are important for maintaining and adapting genomes by facilitating branch migration in homologous recombination pathways.
- RadA is a common bacterial helicase that aids in DNA repair and plays additional roles in natural transformation for some bacteria; while ComM serves a similar purpose in Gram-negative bacteria.
- The study presents cryoEM structures of RadA and ComM with DNA and ATP analogs, highlighting how ATP hydrolysis and DNA binding are interconnected, along with the function of a shared domain in these helicases.
A 47-year-old male with an unremarkable medical history was referred for atypical endodontic pain and treatment of his left upper molars. Clinical and radiographic examinations revealed an extensive, undefined osteolytic area around these teeth. A subsequent bone biopsy diagnosed diffuse large B-cell lymphoma, a high-grade non-Hodgkin's lymphoma.
View Article and Find Full Text PDFCompetence for natural transformation is a central driver of genetic diversity in bacteria. In the human pathogen Streptococcus pneumoniae, competence exhibits a populational character mediated by the stress-induced ComABCDE quorum-sensing (QS) system. Here, we explore how this cell-to-cell communication mechanism proceeds and the functional properties acquired by competent cells grown under lethal stress.
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- Streptococcus pneumoniae can develop competence for DNA transformation, regulated by an autocatalytic loop involving the comCDE and comAB operons.
- Transient temperature increases lead to higher expression levels of the comCDE operon and early competence genes, activating the full competence process, with HtrA chaperone/protease playing a crucial role.
- Other triggers for competence development, like norfloxacin, do not rely on the HtrA pathway, suggesting multiple independent mechanisms for competence induction in response to stress.