The StbA protein, involved in the control of the propagation of genetic material between bacteria has just been characterized by Catherine Guynet (LMGM-CBI) and her collaborators. This protein positions extra-chromosomal DNA molecules, which carry notably antibiotic resistance genes, in bacteria and thus controls their vertical (from the mother bacteria to the daughter bacteria), but also horizontal propagation (between two bacteria, often of different species, by conjugation).
Figure : Diagram showing the different activities of control of plasmid propagation by the multifunctional protein StbA. The control of the propagation pathways, vertical (by segregation to daughter bacteria during cell division) and horizontal (by transfer from one bacterium to another by conjugation), is correlated to the subcellular positioning of plasmids and StbA relative to the bacterial nucleoid and to the transcriptional repression activity of StbA on several genes involved in plasmid establishment after conjugation. StbA is shown in yellow, the nucleoid in pink, genes whose expression is regulated by StbA are indicated by blue arrows, StbA-specific DNA binding sequences by yellow lines, and the origin of conjugative transfer in green.
Characterization of the DNA Binding Domain of StbA, A Key Protein of A New Type of DNA Segregation System. Quèbre V, Del Campo I, Cuevas A, Siguier P, Rech J, Le PTN, Ton-Hoang B, Cornet F, Bouet JY, Moncalian G, de la Cruz F, Guynet C. J Mol Biol. 19 juillet 2022 doi: 10.1016/j.jmb.2022.167752
Contact : Catherine Guynet