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Toledo Arana, Alejandro

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https://academica-e.unavarra.es/handle/2454/50078

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Toledo Arana

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Alejandro

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Instituto de Agrobiotecnología (IdAB)

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0000-0001-8148-6281

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5497

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20222
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Subject: Staphylococcus aureus × Start date: 2020 × End date: 2022 ×

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Now showing 1 - 2 of 2
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    PublicationOpen Access
    Bacterial biofilm functionalization through Bap amyloid engineering
    (Springer Nature, 2022) Matilla Cuenca, Leticia; Taglialegna, Agustina; Gil Puig, Carmen; Toledo Arana, Alejandro; Lasa Uzcudun, Íñigo; Valle Turrillas, Jaione; Ciencias de la Salud; Osasun Zientziak
    Biofilm engineering has emerged as a controllable way to fabricate living structures with programmable functionalities. The amyloidogenic proteins comprising the biofilms can be engineered to create self-assembling extracellular functionalized surfaces. In this regard, facultative amyloids, which play a dual role in biofilm formation by acting as adhesins in their native conformation and as matrix scaffolds when they polymerize into amyloid-like fibrillar structures, are interesting candidates. Here, we report the use of the facultative amyloid-like Bap protein of Staphylococcus aureus as a tool to decorate the extracellular biofilm matrix or the bacterial cell surface with a battery of functional domains or proteins. We demonstrate that the localization of the functional tags can be change by simply modulating the pH of the medium. Using Bap features, we build a tool for trapping and covalent immobilizing molecules at bacterial cell surface or at the biofilm matrix based on the SpyTag/SpyCatcher system. Finally, we show that the cell wall of several Gram-positive bacteria could be functionalized through the external addition of the recombinant engineered Bap-amyloid domain. Overall, this work shows a simple and modulable system for biofilm functionalization based on the facultative protein Bap. © 2022, The Author(s).
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    PublicationOpen Access
    Regulation of heterogenous lexA expression in staphylococcus aureus by an antisense RNA originating from transcriptional read-through upon natural mispairings in the sbrB intrinsic terminator
    (MDPI, 2022) Bastet, Laurène; Bustos-Sanmamed, Pilar; Catalán Moreno, Arancha; Caballero Sánchez, Carlos; Cuesta Ferre, Sergio; Matilla Cuenca, Leticia; Villanueva San Martín, Maite; Valle Turrillas, Jaione; Lasa Uzcudun, Íñigo; Toledo Arana, Alejandro; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua
    Bacterial genomes are pervasively transcribed, generating a wide variety of antisense RNAs (asRNAs). Many of them originate from transcriptional read-through events (TREs) during the transcription termination process. Previous transcriptome analyses revealed that the lexA gene from Staphylococcus aureus, which encodes the main SOS response regulator, is affected by the presence of an asRNA. Here, we show that the lexA antisense RNA (lexA-asRNA) is generated by a TRE on the intrinsic terminator (TTsbrB) of the sbrB gene, which is located downstream of lexA, in the opposite strand. Transcriptional read-through occurs by a natural mutation that destabilizes the TTsbrB structure and modifies the efficiency of the intrinsic terminator. Restoring the mispairing mutation in the hairpin of TTsbrB prevented lexA-asRNA transcription. The level of lexA-asRNA directly correlated with cellular stress since the expressions of sbrB and lexA-asRNA depend on the stress transcription factor SigB. Comparative analyses revealed strain-specific nucleotide polymorphisms within TTsbrB, suggesting that this TT could be prone to accumulating natural mutations. A genome-wide analysis of TREs suggested that mispairings in TT hairpins might provide wider transcriptional connections with downstream genes and, ultimately, transcriptomic variability among S. aureus strains.