Characterization of biofilm formation by Clostridioides difficile

• Autor(a) principal: Bonneville, Lourenço Maria Corrêa Monteiro Cayolla
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/133789
• topic: Clostridioides difficile; biofilm; Veg; Sm-like protein; protein-DNA interaction; Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias

Clostridioides difficile is an urgent threat level enteric pathogen, that can produce endospores, toxins and biofilms. This work focused on understanding the regulatory circuits controlling gene expression during biofilm formation in C. difficile. We characterized the Veg protein, a highly conserved protein among Gram-positive bacteria, and that in B. subtilis was shown to stimulate biofilm formation by inducing biofilm-specific gene expression. Veg, is a 10 kDa, Sm-like protein. Sm proteins form multimers that bind to RNA. We show that overproduction of Veg also stimulated biofilm formation in a C. difficile lab strain. In vitro the oligomeric state of Veg is pH-dependent and shifts the protein from monomer to dimer and higher order protein complexes. We have no evidence for binding to RNA but we show that Veg binds to DNA, specifically to a TA rich region in the cdeM promotor. cdeM is a late sporulation gene involved in assembly of the spore surface layers and whose expression is dependent on yabG, the gene adjacent to veg, coding for a cysteine protease. We propose a model of repression of cdeM by Veg, that could be lifted by proteolysis of Veg by YabG.