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Updated: Jun 8, 2026

Generation of a Gene-disrupted Streptococcus mutans Strain Without Gene Cloning
Published on: October 23, 2017
Development of a versatile procedure based on natural transformation for marker-free targeted genetic modification in
Laetitia Fontaine1, Damien Dandoy, Céline Boutry
1Institut des Sciences de la Vie, Université Catholique de Louvain, Place Croix du Sud 5, Box 6, B-1348 Louvain-la-Neuve, Belgium.
Abstract:
A versatile natural transformation protocol was established for and successfully applied to 18 of the 19 Streptococcus thermophilus strains tested. The efficiency of the protocol enables the use of in vitro-amplified mutagenesis fragments to perform deletion or insertion of large genetic fragments. Depending on the phenotype linked to the mutation, markerless mutants can be selected either in two steps, i.e., resistance marker insertion and excision using an adapted Cre-loxP system, or in one step using a powerful positive screening procedure as illustrated here for histidine prototrophy.
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