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TnFLXopen: Markerless Transposons for Functional Fluorescent Fusion Proteins and Protein Interaction Prediction

Fluorescence microscopy of cells expressing proteins translationally linked to a fluorophore can be a powerful tool to investigate protein localization dynamics in vivo. One major obstacle to reliably analyze biologically relevant localization is the construction of a fusion protein that is both flu...

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Autores principales: Dempwolff, Felix, Kearns, Daniel B.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Society for Microbiology 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9241775/
https://www.ncbi.nlm.nih.gov/pubmed/35499319
http://dx.doi.org/10.1128/spectrum.02428-21
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author Dempwolff, Felix
Kearns, Daniel B.
author_facet Dempwolff, Felix
Kearns, Daniel B.
author_sort Dempwolff, Felix
collection PubMed
description Fluorescence microscopy of cells expressing proteins translationally linked to a fluorophore can be a powerful tool to investigate protein localization dynamics in vivo. One major obstacle to reliably analyze biologically relevant localization is the construction of a fusion protein that is both fluorescent and functional. Here, we develop a strategy to construct fluorescent fusions at theoretically any location in the protein by using TnFLXopen random transposon mutagenesis to randomly insert a gene encoding a fluorescent protein. Moreover, insertions within a target gene are enriched by an inducible gene-trap strategy and selection by fluorescence activated cell sorting. Using this approach, we isolate a variety of fluorescent fusions to FtsZ that exhibit ring-like localization and a fusion to the flagellar stator protein that both is functional for supporting motility and localizes as fluorescent puncta. Finally, we further modify TnFLXopen to insert the coding sequence for the C-terminal half of mVenus for use in bimolecular fluorescence complementation (BiFC) and the in vivo detection of protein-protein interaction candidates. As proof-of-concept, the DivIVA polar scaffolding protein was fused to the N terminus of mVenus, the C terminus of mVenus was delivered by transposition, and a combination of fluorescence activated cell sorter (FACS) sorting and whole-genome sequencing identified the known self-interaction of DivIVA as well as other possible candidate interactors. We suggest that the FACS selection is a viable alternative to antibiotic selection in transposon mutagenesis that can generate new fluorescent tools for in vivo protein characterization. IMPORTANCE Transposon mutagenesis is a powerful tool for random mutagenesis, as insertion of a transposon and accompanying antibiotic resistance cassette often disrupt gene function. Here, we present a series of transposons with fluorescent protein genes which, when integrated in frame, may be selected with a fluorescence activated cell sorter (FACS). An open reading frame runs continuously through the transposon such that fluorescent protein fusions may be inserted theoretically anywhere in the primary sequence and potentially preserve function of the target protein. Finally, the transposons were further modified to randomly insert a partial fluorescent protein compatible with bimolecular fluorescence complementation (BiFC) to identify protein interaction candidates.
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spelling pubmed-92417752022-06-30 TnFLXopen: Markerless Transposons for Functional Fluorescent Fusion Proteins and Protein Interaction Prediction Dempwolff, Felix Kearns, Daniel B. Microbiol Spectr Research Article Fluorescence microscopy of cells expressing proteins translationally linked to a fluorophore can be a powerful tool to investigate protein localization dynamics in vivo. One major obstacle to reliably analyze biologically relevant localization is the construction of a fusion protein that is both fluorescent and functional. Here, we develop a strategy to construct fluorescent fusions at theoretically any location in the protein by using TnFLXopen random transposon mutagenesis to randomly insert a gene encoding a fluorescent protein. Moreover, insertions within a target gene are enriched by an inducible gene-trap strategy and selection by fluorescence activated cell sorting. Using this approach, we isolate a variety of fluorescent fusions to FtsZ that exhibit ring-like localization and a fusion to the flagellar stator protein that both is functional for supporting motility and localizes as fluorescent puncta. Finally, we further modify TnFLXopen to insert the coding sequence for the C-terminal half of mVenus for use in bimolecular fluorescence complementation (BiFC) and the in vivo detection of protein-protein interaction candidates. As proof-of-concept, the DivIVA polar scaffolding protein was fused to the N terminus of mVenus, the C terminus of mVenus was delivered by transposition, and a combination of fluorescence activated cell sorter (FACS) sorting and whole-genome sequencing identified the known self-interaction of DivIVA as well as other possible candidate interactors. We suggest that the FACS selection is a viable alternative to antibiotic selection in transposon mutagenesis that can generate new fluorescent tools for in vivo protein characterization. IMPORTANCE Transposon mutagenesis is a powerful tool for random mutagenesis, as insertion of a transposon and accompanying antibiotic resistance cassette often disrupt gene function. Here, we present a series of transposons with fluorescent protein genes which, when integrated in frame, may be selected with a fluorescence activated cell sorter (FACS). An open reading frame runs continuously through the transposon such that fluorescent protein fusions may be inserted theoretically anywhere in the primary sequence and potentially preserve function of the target protein. Finally, the transposons were further modified to randomly insert a partial fluorescent protein compatible with bimolecular fluorescence complementation (BiFC) to identify protein interaction candidates. American Society for Microbiology 2022-05-02 /pmc/articles/PMC9241775/ /pubmed/35499319 http://dx.doi.org/10.1128/spectrum.02428-21 Text en Copyright © 2022 Dempwolff and Kearns. https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license (https://creativecommons.org/licenses/by/4.0/) .
spellingShingle Research Article
Dempwolff, Felix
Kearns, Daniel B.
TnFLXopen: Markerless Transposons for Functional Fluorescent Fusion Proteins and Protein Interaction Prediction
title TnFLXopen: Markerless Transposons for Functional Fluorescent Fusion Proteins and Protein Interaction Prediction
title_full TnFLXopen: Markerless Transposons for Functional Fluorescent Fusion Proteins and Protein Interaction Prediction
title_fullStr TnFLXopen: Markerless Transposons for Functional Fluorescent Fusion Proteins and Protein Interaction Prediction
title_full_unstemmed TnFLXopen: Markerless Transposons for Functional Fluorescent Fusion Proteins and Protein Interaction Prediction
title_short TnFLXopen: Markerless Transposons for Functional Fluorescent Fusion Proteins and Protein Interaction Prediction
title_sort tnflxopen: markerless transposons for functional fluorescent fusion proteins and protein interaction prediction
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9241775/
https://www.ncbi.nlm.nih.gov/pubmed/35499319
http://dx.doi.org/10.1128/spectrum.02428-21
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